Luminous Landscape Forum
Equipment & Techniques => Cameras, Lenses and Shooting gear => Topic started by: david o on February 21, 2007, 11:26:05 pm
-
check here
http://www.usa.canon.com/templatedata/pres...21_1dmark3.html (http://www.usa.canon.com/templatedata/pressrelease/20070221_1dmark3.html)
-
I'm a fan.
-
Good diss by Canon to all of us waiting for 22/24mp
Regards
Danijela
-
YAWN... i am interested to see the real improvements in the 16-35mm II L lens but I guess i am going to wait until next round for the 1Dsmk2 replacement.
check here
http://www.usa.canon.com/templatedata/pres...21_1dmark3.html (http://www.usa.canon.com/templatedata/pressrelease/20070221_1dmark3.html)
[a href=\"index.php?act=findpost&pid=102258\"][{POST_SNAPBACK}][/a]
-
I noticed 14bits...
-
Yawn? Look at the press release, live preview, "silent drive mode", lighter, new controls, 19 cross-type AF sensors, they put a heck of a lot of new into this.
-
Nice looking camera. Where is the print button?
Not at all what I was hoping for. Looking a lot like I'm going to have a pentax k10d with the two new pentax lenses (announced a while ago, availability announced today) announced today. Unless, of course, canon actually has something else up their sleeve.
Bah! Been waiting for canon to announce ever since I mangled my 20D.
-
Yawn? Look at the press release, live preview, "silent drive mode", lighter, new controls, 19 cross-type AF sensors, they put a heck of a lot of new into this.
[a href=\"index.php?act=findpost&pid=102269\"][{POST_SNAPBACK}][/a]
You see how many shots they are claiming? Insane. People over at DPreview are whining about the 10mp. I don't think they're the target market.
-
You see how many shots they are claiming? Insane. People over at DPreview are whining about the 10mp. I don't think they're the target market.
[a href=\"index.php?act=findpost&pid=102278\"][{POST_SNAPBACK}][/a]
Yeah, the drive is rediculous. Learn some timing.
-
This is good news; the updated camera seems to deliver more than I expected, if I could only recall my expectations.
Personally, I'll also wait for further announcements this year to see which model I'm going to upgrade to, if I'm going to upgrade.
Edit: I suddenly noticed the little string of text that ought to have Phil Askey whooping with joy:
To avoid corruption of captured images, a warning appears on the LCD and an alarm sounds if the memory card door is opened while images are still being written.
I also noticed that the new EF 16-35mm f/2.8L II USM has an 82mm filter diameter. Yow, there goes my filter budget.
-
Gotta say, I am decidedly underwhelmed by the extent of Canon's new gear releases. This is their 70th anniversary year and the 20th anniversary this March of EOS, but it feels like the celebrations are no more than a couple of smouldering firecrackers and a sparkler, rather than more fitting big bang fireworks.
I'm sure the sports shooters are interested but that must be a fairly tiny fraction of their market. The new 16-35 might be of interest but I have just bought one of the current ones, so gonna wait quite a while to see how it reviews before even thinking of trading in.
I think Canon are shooting themselves in the foot with their strict non-disclosure policy before launches. All it does is allow expectations to run too high, which can only lead to disappointment when the real products are released, even when the new kit is pretty decent, like with the new 1D MkIII.
I do a fair bit of photo workshop teaching and I am always heralding Canon as being the leaders in the prosumer market, but Nikon, Sony et al are making it harder to keep saying that with conviction. Canon are going to lose a lot of sales this year now that the 30D hasn't been replaced.
At least my bank manager will stay happy as I won't be raiding the funds for any of this new Canon kit.
Steve
-
Gotta say, I am decidedly underwhelmed by the extent of Canon's new gear releases. This is their 70th anniversary year and the 20th anniversary this March of EOS, but it feels like the celebrations are no more than a couple of smouldering firecrackers and a sparkler, rather than more fitting big bang fireworks.
I'm sure the sports shooters are interested but that must be a fairly tiny fraction of their market. Canon are going to lose a lot of sales this year now that the 30D hasn't been replaced.
At least my bank manager will stay happy as I won't be raiding the funds for any of this new Canon kit.
Steve
[a href=\"index.php?act=findpost&pid=102313\"][{POST_SNAPBACK}][/a]
So you're writing the rest of the year off as far as new models are concerned? Brave man.
The sports shooters are a very large part of Canon's EOS1 market, so today's release is major news for them!
As far as a 1DsMkII replacement is concerned (which I'm waiting for) then the 1DMkIII feature set is a very promising pointer to what to expect - I hope. 14bit is again a major feature!
For what it is worth, I've been told (from someone who is in a position to know) that Canon's entire DSLR line-up will be changed this year. I just wish the 1DsMkII had been the first!
-
So you're writing the rest of the year off as far as new models are concerned? Brave man.
[a href=\"index.php?act=findpost&pid=102314\"][{POST_SNAPBACK}][/a]
Not writing off the rest of the year, as I am sure there will be more releases eventually, but think Canon will lose out between now and then because there are a lot of people revved up now for a 40D, in particular, who will quite possibly look elsewhere and find cameras that match their needs.
I'm holding out for a new 5D to back up the 1DS MkII, but there again the 1DS MKIII will no doubt pull on my purse strings. I was kinda hoping that the 5D replacement would come out now too, or at least the 40D, as I have a big project ahead and it would have been perfect. Can't see me buying a current 5D or 30D though, as they will nosedive in value once the new ones arrives.
Steve
-
If you go through all the new features, it is actually a very smart upgrade. 1.3x sensor is a bit of a disappointment but sport shooters love the artificial lenghtening of their lenses. Everything else is a long step in the right direction. Did you notice the mirror lock feature... Michael is going to be happy. 2200 shots with one battery with a % indicator? AF point selection with the joystick? Fine tuning of the AF for each lens (that will change my life)! Custom modes? 14 bits (4 times as many gradations!). For sport shooters, the live preview is especially good used remotely, as it will be for studio shooters with the 1Ds3 if it has the same feature, the one thing that was missing with tethered shooting. As a wildlife photographer, I welcome the finally waterproof 580 EX II and the other new flash functions. As a 1 series user, I am quite happy the main functions don't have to be relearnt and that the format of the camera remains the same. Brilliant! Oh, and it is cheaper too....
As for the 1Ds3, it is probably ready but waits for feedback on the 1D3 just in case. Now I am really getting impatient.
-
If you go through all the new features, it is actually a very smart upgrade. 1.3x sensor is a bit of a disappointment but sport shooters love the artificial lenghtening of their lenses. Everything else is a long step in the right direction. Did you notice the mirror lock feature... Michael is going to be happy. 2200 shots with one battery with a % indicator? AF point selection with the joystick? Fine tuning of the AF for each lens (that will change my life)! Custom modes? 14 bits (4 times as many gradations!). For sport shooters, the live preview is especially good used remotely, as it will be for studio shooters with the 1Ds3 if it has the same feature, the one thing that was missing with tethered shooting. As a wildlife photographer, I welcome the finally waterproof 580 EX II and the other new flash functions. As a 1 series user, I am quite happy the main functions don't have to be relearnt and that the format of the camera remains the same. Brilliant! Oh, and it is cheaper too....
As for the 1Ds3, it is probably ready but waits for feedback on the 1D3 just in case. Now I am really getting impatient.
[a href=\"index.php?act=findpost&pid=102317\"][{POST_SNAPBACK}][/a]
Imagine the coming 1Ds MK3 have all these features and perhaps a quad Digit III? Can't wait to see what's coming in days!
-
Live LCD preview (also available on the computer when tethered), 3-inch LCD, integrated sensor cleaning, an additional stop's worth of ISO, and sRAW when lower-resolution images are OK but RAW flexibility is desired, Li-ion battery instead of NiMH, and 14-bit RAW. I'd say overall a nice set of new features.
Given the 2:1 pixel ratio between the 1Ds-II and 1D-II, a 20MP+ pixel count for the 1Ds-III is quite plausible.
-
Imagine the coming 1Ds MK3 have all these features and perhaps a quad Digit III? Can't wait to see what's coming in days!
[a href=\"index.php?act=findpost&pid=102320\"][{POST_SNAPBACK}][/a]
Yes. Trade some of the internal space taken up by the extra mirror and shutter motors for more processing electronics and say 5-6fps.
-
Yes. Trade some of the internal space taken up by the extra mirror and shutter motors for more processing electronics and say 5-6fps.
Extra mirror and shutter motors?
Where do you have that information from?
-
Extra mirror and shutter motors?
Where do you have that information from?
[a href=\"index.php?act=findpost&pid=102340\"][{POST_SNAPBACK}][/a]
The white paper.
Pages 31 & 35.
-
if the target of that is sport photographer (with 10 fps how could it be different) I don't see the point to have live preview.
How that could work with a 300/2.8 followong is subject? can you picture the guy with that lens holding his camera to see what's goin' on on the display... Sounds weard to me.
But I must missed something here.
Anyhow it's not the product I'm looking for, just a thought about that feature.
-
Just noticed that the "multi controller" joystick wasn't used for AF point selection. What a shame, it's my favorite feature of the 5D and sorely missing on the 1D/1Ds. Selecting with the wheels is just too slow and awkward for wildlife.
For the previous message, a lot of sports shooting is actually done remotely and/or from very awkward angles. With the wi-fi controller (and hoping that the other 200 cameras using the same system won't cause too much interference) you can see what you are taking and even adjust parameters on the fly. Somebody might even come up with a robotised tripod head to help with framing... Anyway, it doesn't cost anymore to have it, so why not..
I'll certainly get one to go with the long lenses and if the 1Ds3 is the same with a full frame sensor (whatever the resolution, 2 extra bits is already reason enough) I'll get one of these as well.
-
The white paper.
Pages 31 & 35.
And where is this white paper? It's not readily available from www.usa.canon.com, at least.
Could you provide a link?
-
For those who missed it, general information on the D3 is at:
http://www.robgalbraith.com/public_files/C...White_Paper.pdf (http://www.robgalbraith.com/public_files/Canon_EOS-1D_Mark_III_White_Paper.pdf)
and
http://web.canon.jp/Imaging/eos1dm3/ (http://web.canon.jp/Imaging/eos1dm3/)
but see the rest of the RobGalbraith announcement as well, including the press release.
-
The majority of Canon's market is PJs -- covering news and sporting events. If you've ever seen a news or sports press conference, you see PJs all the time holding cameras above their heads not looking thru the viewfinder so that they can get the shot without being blocked. Well, I think Live View is entirely appropriate here.
I'm really quite impressed with what they've done here in one package. Going up to 10 AND increasing the A/D to 14-bit AND up to 10 fps AND up to 30 RAWs per burst is pretty remarkable. And then there are all the little things, such as the fact that it's 1/2 pound lighter, bigger LCD, dust-cleaning system, etc.
People have wanted personal functions to be settable in the camera instead of via computer. Well Canon listened and did that too.
People have lambasted Canon for bad wide-angle lens performance esp. in corners. So Canon releases a new 16-35 f/2.8 II that is designed specifically to address this. Whether it actually does or not remains to be seen. But the effort is there to fix it.
Pretty cool.
-
The majority of Canon's market is PJs -- covering news and sporting events. If you've ever seen a news or sports press conference, you see PJs all the time holding cameras above their heads not looking thru the viewfinder so that they can get the shot without being blocked. Well, I think Live View is entirely appropriate here.
[a href=\"index.php?act=findpost&pid=102360\"][{POST_SNAPBACK}][/a]
I've just printed off the white paper, but it doesn't look like the LCD is articulated... so when they hold it over their heads and point back down, there's no way to see the preview regardless.
-
so when they hold it over their heads and point back down, there's no way to see the preview regardless.
[a href=\"index.php?act=findpost&pid=102363\"][{POST_SNAPBACK}][/a]
I thought about that and again here's a point...
but don't get me wrong it could be usefull, but I ever shot car races (Rallies, F1) and I know that even with wide angle, so imagine with 300mm, there's no way to me that live preview is usable.
And I'm sure that the camera was tested during the superbowl and is there anybody noticed someone shooting from is chair...
but again nothing wrong to have it. It wont hurt for sure.
-
Nice, larger display! But I don't see a 1ds MKIII with a higher pixel count, canon went for bigger pixels on the new camera, will that be the future trend?
-
Well these are better pixels. 14-bit A-to-D for smoother tones, less quantization problems in shadows, and a more efficient microlens array for better light-gathering efficiency. Translation: cleaner images with less noise, and the option of higher ISO. I think that's much preferable to just adding pixels without the pixels themselves getting any better.
-
if the target of that is sport photographer (with 10 fps how could it be different) I don't see the point to have live preview.
How that could work with a 300/2.8 followong is subject? can you picture the guy with that lens holding his camera to see what's goin' on on the display... Sounds weard to me.
But I must missed something here.
Anyhow it's not the product I'm looking for, just a thought about that feature.
[a href=\"index.php?act=findpost&pid=102346\"][{POST_SNAPBACK}][/a]
I suspect the main target is sports, pj, wedding, event, etc. I also suspect that they listened to a bunch of working pros who might do one of those primarily *and* a smaller amount of studio work and didn't want to buy a 1Ds... hence the addition of this feature. Pure speculation on my part though.
-
Canon went for bigger pixels on the new camera
[a href=\"index.php?act=findpost&pid=102377\"][{POST_SNAPBACK}][/a]
Canon went for closer pixel spacing than on the model it replaces (1DMkIIN), and the same as on the 1Ds MkII, but with better high ISO performance than either of those previous models, thanks to technological improvements in micro-lenses and such.
The trend continues to be towards higher resolution through lower pixel spacing, without the IQ sacrifices that people fear when they ignore the room for technological improvement at any given pixel spacing.
-
Small Review (http://www.dpreview.com/news/0702/07022208canoneos1dmarkiii.asp)
You could watch TV on the LCD lol
-
As far as I know, the EOS-1 D models sell considerably better than the EOS-1Ds ones, partly because of Canon;s very important PJ/sports user base, but probably also because they are far less expensive. And Canon has again indicated in the 1DMkIII white paper that this cost differential is likely to persist, saying that the 1DMkIII sensor can be fabricated in "one pass" while "FF" sized ones cannot.
For this reason alone, they are of interest for other types of photography besides action. So following Olympus with Live View (even using the same name!) should be great for situations like manual focus with the camera on a tripod.
Also, there is the prospect of remote operation of a camera, say located in the ceiling of an arena, with wired or wireless VF feed to a controlling computer. Pre-focus needed though; like focusing on the rim and shooting the dunk at 10fps.
-
For this reason alone, they are of interest for other types of photography besides action. So following Olympus with Live View (even using the same name!) should be great for situations like manual focus with the camera on a tripod.
Yes, I can imagine that it would be great for not only high-quality reproductions, but also for micro/macro work, which can sometimes be a pain with a regular viewfinder.
-
Live LCD preview (also available on the computer when tethered), 3-inch LCD, integrated sensor cleaning, an additional stop's worth of ISO, and sRAW when lower-resolution images are OK but RAW flexibility is desired, Li-ion battery instead of NiMH, and 14-bit RAW. I'd say overall a nice set of new features.
Given the 2:1 pixel ratio between the 1Ds-II and 1D-II, a 20MP+ pixel count for the 1Ds-III is quite plausible.
[a href=\"index.php?act=findpost&pid=102333\"][{POST_SNAPBACK}][/a]
The sRAW feature (which sounds like 4:1 hardware pixel binning) would be very useful with a 20 or 24 MP sensor, giving 5-6MP output, which is plenty for many applications. It will be interesting to see the signal to noise ratio in this mode.
Bill
-
WOW! I'm not the target consumer, but the laundry list of significant features/improvements is awesome! There is some really high-end stuff in there that will surely transfer/morph to the rest of the line as well! NICE!!!
-
Canon went for closer pixel spacing than on the model it replaces (1DMkIIN), and the same as on the 1Ds MkII, but with better high ISO performance than either of those previous models, thanks to technological improvements in micro-lenses and such.
The trend continues to be towards higher resolution through lower pixel spacing, without the IQ sacrifices that people fear when they ignore the room for technological improvement at any given pixel spacing.
[{POST_SNAPBACK}][/a] (http://index.php?act=findpost&pid=102394\")
It is also worthwhile to note that Canon increases the MP count only when they can do so without compromising the low noise characteristics for which they are known. As I am sure you know, Moore's law applies only partially to CMOS sensor scaling as described in a Stanford article by Wandell et al [a href=\"http://white.stanford.edu/~brian/papers/ise/CMOSRoadmap-2005-SPIE.pdf]Moore meets Planck and Sommerfeld[/url]. Planck has to do with quantum efficiency and Sommerfled with diffraction. In their 1D M3 white paper, Canon reports that they kept the photo-sensitive area of the pixels about the same, but shrank the transistor size and improved the microlenses.
I don't know what the fill factor of the new Canon sensor is, but with CMOS technology a considerable amount of space is taken up by the on chip processing transistors, leaving less room for the photosensitive elements. As Wandel points out scaling can be used to decrease the pixel size and improve spatial resolution or to shrink the transistor size and increase the photosensitive area. As pixel size decreases, the f/ratio of the microlenses becomes limited.
Although technology is wonderful, limits imposed by the laws of physics are being reached.
Bill
-
So the second pass to build the sensor translates to roughly $4 or $5K retail? They've got the horesepower to do 10mpx at 10 fps with a pair of chips, surely no incremental cost to handle 22 mpx at 4 fps? Having said that I realize it's the market that determines the price they're able to command.
As for live preview, I agree that it doesn't make a lot of sense for sports/PJ (other than the remote capture) I'd guess they're "prototyping" it for the 1ds3 release.
-
So the second pass to build the sensor translates to roughly $4 or $5K retail?
[a href=\"index.php?act=findpost&pid=102443\"][{POST_SNAPBACK}][/a]
About $3K or more it seems: that was the price gap from 1DMkII to the 1Ds or 1DsMkII, the 1DMkIII will cost about the same as the 1DsMkII, and I predict that any 1DsMkIII will continue to cost about as much as the first two 1Ds versions.
It is three passes for the 1DsMkII sensor according to Canon, and one cost factor is probably far more rejected sensors, when the passes do not line up well enough.
live preview ... doesn't make a lot of sense for sports/PJ (other than the remote capture)
[a href=\"index.php?act=findpost&pid=102443\"][{POST_SNAPBACK}][/a]
Firstly, isn't helping remote capture already worthwhile? Secondly, 1D's are often used for tasks other than sports/PJ, some of which can benefit from live preview at high magnification for manual focusing. Arguably, with resolution increasing beyond what film offered and VF's having lower magnification that in the manual focus era and lacking focusing aids, it is harder than ever to manual focus with sufficient accuracy through a DSLR's OVF. Supposedly the image in an SLR OVF has only about as much detail as a 2MP image.
But anyway, I agree in expecting Live View in many or all future Canon SLR's. The CMOS sensors have the inherent capability, so adding the feature should cost almost nothing.
-
As pixel size decreases, the f/ratio of the microlenses becomes limited.
Although technology is wonderful, limits imposed by the laws of physics are being reached.
Bill
[a href=\"index.php?act=findpost&pid=102434\"][{POST_SNAPBACK}][/a]
I would imagine that some of the first applications of the 'superlens', constructed from metamaterials with a negative refractive index, will be for microlenses in imaging devices. Often when we think no further progress is possible because we've hit the barrier of the so-called laws of physics, some imaginative breakthrough turns up to circumvent that apparent obstacle.
-
I would imagine that some of the first applications of the 'superlens', constructed from metamaterials with a negative refractive index, will be for microlenses in imaging devices. Often when we think no further progress is possible because we've hit the barrier of the so-called laws of physics, some imaginative breakthrough turns up to circumvent that apparent obstacle.
[a href=\"index.php?act=findpost&pid=102475\"][{POST_SNAPBACK}][/a]
Ray,
A little knowledge can be dangerous.
Current superlenses consist mainly of wires and split-ring resonators (SRRs), which work for radio waves, but constructing a super lens at optical wave lenghts is difficult since not only must the index of refraction equal -1, but also requires that both ε (electrical permittivity) = -1 and µ (magnetic permeability) = -1. A lens that falls short of this ideal suffers from drastically degraded resolution. (THE QUEST FOR THE Superlens., By: Pendry, John B., Smith, David R., Scientific American, 00368733, Jul2006, Vol. 295, Issue 1).
If the object distance is very close to the image distance, these conditions can be relaxed, and a very thin layer of metal can act as a superlens, possibly useful for micro lithography in constructing semiconductor chips, but this wouldn't work for a camera lens.
We are a long way from a super lens for cameras, but perhaps someday such a lens can be constructed. I would not expect it before the next PMA show.
Bill
-
We are a long way from a super lens for cameras, but perhaps someday such a lens can be constructed. I would not expect it before the next PMA show.
[a href=\"index.php?act=findpost&pid=102481\"][{POST_SNAPBACK}][/a]
Bill,
I don't think I was implying it would be easy. Building a full scale camera lens from such materials might never happen in our lifetime, but building a microlens just a couple of microns in diameter is another matter.
Interestingly, a superlens at optical frequencies has already been constructed in the labs, but through a different process than use of metamaterials. Here's a reference from Wikipedia.
In 2005, the first optical superlens was constructed by physicists at University of California, Berkeley. This allowed scientists to observe objects as small as 40 nm—one-tenth the size of objects which can be viewed with conventional optical microscopes. The superlens constructed at UC Berkeley did not employ a negative refractive index metamaterial as in Pendry's perfect lens. Instead a thin film of silver was used to amplify the evanescent waves.
-
Interestingly, a superlens at optical frequencies has already been constructed in the labs, but through a different process than use of metamaterials. Here's a reference from Wikipedia.
[a href=\"index.php?act=findpost&pid=102485\"][{POST_SNAPBACK}][/a]
That is the same group referenced by Pendry in the Scientific American paper. As I interpret the article, the index of refraction was negative as was permittivity (ε). With this lens the distance between the object and image is smaller than the wavelength of the light, hardly practical with a camera.
"But we cannot yet fabricate a material that yields µ = -1 at visible wavelengths. Fortunately, a compromise is possible. When the distance between the object and the image is much smaller than the wavelength, we need only fulfill the condition ε = -1, and then we can disregard µ. Just last year Richard Blaikie's group at the University of Canterbury in New Zealand and Xiang Zhang's group at the University of California, Berkeley, independently followed this prescription and demonstrated super-resolution in an optical system. At optical wavelengths, the inherent resonances of a metal can lead to negative permittivity (ε). Thus, a very thin layer of metal can act as a superlens at a wavelength where ε = -1.
Both Blaikie and Zhang used a layer of silver about 40 nanometers thick to image 365-nanometer-wavelength light emanating from shaped apertures smaller than the light's wavelength. Although a silver slab is far from the ideal lens, the silver superlens substantially improved the image resolution, proving the underlying principle of superlensing."
Bill
-
That is the same group referenced by Pendry in the Scientific American paper. As I interpret the article, the index of refraction was negative as was permittivity (ε). With this lens the distance between the object and image is smaller than the wavelength of the light, hardly practical with a camera.
[a href=\"index.php?act=findpost&pid=102494\"][{POST_SNAPBACK}][/a]
But Bill, I've just written that I don't expect a fully functioning camera lens made from metamaterials to be available in my lifetime. Microlenses are a different kettle of fish though, don't you agree?
As you must have gathered, I'm a technology optimist. I don't know enough to understand why certain developments are impossible. However, it's apparent that sometimes things that seem impossible from a practical viewpoint can become feasible as developments take place in other disciplines, especially in computer science.
In Australia we are having a political debate about nuclear energy in light of the fact we have so much uranium but are getting most of our energy from burning coal.. But the holy grail of energy production has always been the development of the fusion reactor, something which Australia seems not to be involved with.
.... the world's top industrial nations — including the United States, Russia and the European Union — signed an agreement to build the world's first full-scale nuclear fusion reactor, the $A15 billion International Thermonuclear Experimental Reactor project (ITER). After the International Space Station, ITER says, it is the world's biggest science project.
Nuclear fission, nuclear fusion — what's the difference? Fusion has been mooted for decades as the next generation of nuclear power, one that uses hydrogen instead of uranium.
There is a virtually limitless supply of fuel, say supporters, as hydrogen can be extracted from seawater. Moreover, fusion produces little radioactive waste — one of the main worries about fission — and no greenhouse gases. It promises, say supporters, nothing less than a world where energy and global warming concerns are solved.
This idea has been kicking around for many decades. I'm glad someone is still working on it and taking it seriously. I guess you don't spend $15 billion without some expectation of success.
Another theoretically possible technological breakthrough of great consequence is the Quantum computer. They are still wotking on that too.
Science Daily — Physicists at the Commerce Department's National Institute of Standards and Technology (NIST) have taken a significant step toward transforming entanglement--an atomic-scale phenomenon described by Albert Einstein as "spooky action at a distance"--into a practical tool. They demonstrated a method for refining entangled atom pairs (a process called purification) so they can be more useful in quantum computers and communications systems, emerging technologies that exploit the unusual rules of quantum physics for pioneering applications such as "unbreakable" data encryption.
The NIST process for "purifying" an unusual property of quantum physics called entanglement involves illuminating two pairs of beryllium ions (charged atoms) with a series of ultraviolet laser pulses. (Credit: Bill Pietsch, Astronaut 3 Media)Ads by Google Advertise on this site
The NIST work, reported in the Oct. 19, 2006, issue of Nature,* marks the first time atoms have been both entangled and subsequently purified; previously, this process had been carried out only with entangled photons (particles of light). The NIST demonstration also is the first time that scientists have been able to purify particles nondestructively. Direct measurement would destroy the delicate entangled state of atom pairs; the new experiment gets around this problem by entangling two pairs of atoms and measuring only one pair.
-
Personally, I think the biggest new feature is one that most people seem to have overlooked.
The name rhymes.
1Deeeeeeeeeeeeeeeeeee Mark Threeeeeeeeeeeeeeeeeeeeee
-
The majority of Canon's market is PJs -- covering news and sporting events. If you've ever seen a news or sports press conference, you see PJs all the time holding cameras above their heads not looking thru the viewfinder so that they can get the shot without being blocked. Well, I think Live View is entirely appropriate here.
[a href=\"index.php?act=findpost&pid=102360\"][{POST_SNAPBACK}][/a]
I have done press and sports with the 1d MkII and while live view would be a great thing here at the 1d Mark III it is not well made, think twice .... the screen is fixed in the body ! so for the overhead shots you can forget this feature. Might be that some other use is found for that feature.
This is certainly a great evolution of a great camera, but if Canon want to make the next leap, they have to say goodby to the outdated body of the 1d series.
-
Basically, I'm concerned with raw performance rather than bells and whistles. (That's raw as in sheer). Canon seems to have delivered this. Sometimes they make minor improvements, as in the 30D, but mostly major improvements as in the 1D3.
As I recall, the 1D Mkll preceded the 1Ds2 which preceded the 5D. The upgrades will probably follow the same pattern, which means I could expect an upgrade to the 5D around October this year.
It almost goes without saying, there'll be greater pixel count, improved shadow noise, a 6400 ISO setting, auto-cleaning sensor and larger LCD screen. Hopefully there'll be a few surprises also.
-
I think this quote from IR says it all really.
"...The EOS 1D Mark III isn't just for sports anymore. It's a more universal camera for the vast majority of pro photographers. With the multiple improvements in the new camera, photographers will no longer need to trade off resolution, image quality, and speed against each other. The 1D Mark III now has enough of all three to satisfy a huge slice of the market in a single camera body..."
/www.imaging-resource.com/PRODS/E1DMK3/E1DMK3A.HTM
I have been using a 1DMkII for several years now for everything from MotoGP to interiors, with great success. If I wasn't after bigger file sizes I'd already have my order in! As it is, looks like I'm waiting 'til later in the year.
-
Anybody know if there be a live histogram with the Live View feature?
-
Anybody know if there be a live histogram with the Live View feature?
It's a bit unclear in the white paper, but it appears that there will be if you have enabled exposure simulation (which is what the relevant custom function is about):
Below the image, the shutter speed, aperture, exposure level (exposure compensation
amount, AEB level), flash exposure level, shots remaining, and ISO speed are displayed.
In the magnified view, the magnified location, magnification, and AE lock status are
displayed on the right of the image. In addition, when you press the INFO button, the
Picture Style, battery check, AE lock status, and flash-ready are also displayed on the
lower left of the image. If C. Fn IV -16-1 is set and you press the INFO button again, a
brightness or RGB histogram appears on the right of the image. (For flash shots and
bulb, the histogram display will be grayed out.)
Press the INFO button again and only the Live View image (without information) will be
displayed.
-
Looks like we finally have our one-touch mirror lockup ... turning on Live View will lock up the mirror.
-
Looks like we finally have our one-touch mirror lockup ... turning on Live View will lock up the mirror.
But turning on Live View isn't a one-touch operation, unless I've misread something.
-
But turning on Live View isn't a one-touch operation, unless I've misread something.
[a href=\"index.php?act=findpost&pid=102626\"][{POST_SNAPBACK}][/a]
All you have to do is press the SET button, which is right on the back of the camera. See page 23 of the White Paper.
-
You have to have Live View enabled (custom function). After that, SET button will work to bring the mirror up...
-
... scaling can be used to decrease the pixel size and improve spatial resolution or to shrink the transistor size and increase the photosensitive area. As pixel size decreases, the f/ratio of the microlenses becomes limited.
Although technology is wonderful, limits imposed by the laws of physics are being reached.
[a href=\"index.php?act=findpost&pid=102434\"][{POST_SNAPBACK}][/a]
Compact digicam sensors with photo-site spacing less than 2 microns might be approaching those limits, but I doubt that DSLR sensors are anywhere close.
For example, micro-lenses work fairly well on 2 micron digicam pixels.
As far as reducing transistor size, the newly announce Sony CMOS 1/1.8" sensor with 2.5 micron pixel spacing uses 180nm process, giving far larger minimum component size than the newer 90nm and 60nm processes. So even "tiny" digicam pixels are not yet pushing hard at the limits of miniaturization, and seem to have room for reducing transistor size to half or less what it is now.
-
Compact digicam sensors with photo-site spacing less than 2 microns might be approaching those limits, but I doubt that DSLR sensors are anywhere close.
[{POST_SNAPBACK}][/a] (http://index.php?act=findpost&pid=102680\")
Well, do you have any information on what the fill factor of the Canon CMOS chips is? Even if the fill factor approaches 100 percent and the transistor area of the chip is markedly reduced, you still need a sufficient active pixel area to capture photons. The quantum efficiency could be doubled or tripled, but you still have to have a sufficient pixel size to control shot noise and maintain and dynamic range and sensitivity. These factors are summarized by [a href=\"http://www.clarkvision.com/imagedetail/digital.sensor.performance.summary/]Roger Clark[/url]. Do you have this additional information?
Bill
-
Even if the fill factor approaches 100 percent and the transistor area of the chip is markedly reduced, you still need a sufficient active pixel area to capture photons. [a href=\"index.php?act=findpost&pid=102697\"][{POST_SNAPBACK}][/a]
Apart from the greater expense of fabrication, is there any insurmountable obstacle to mounting all the photon receptors and microlenses on one side of the chip and all the processing transistors on the other side, thus providing close to 100% fill factor?
This could be the next step to eke out the maximum dynamic range from a sensor of a given size. Another approach might be to increase the well depth and use the microlens to precisely direct the light vertically down into the well, which I think is already being done towards the edges of the sensor.
There are no doubt lots of improvements that can be implemented before we hit the brick wall of 'the laws of physics'. However, I've often wondered to what extent diffraction degrades the preformance of microlenses. Is it significant ot not, and if so, at what size does it become significant?
-
Apart from the greater expense of fabrication, is there any insurmountable obstacle to mounting all the photon receptors and microlenses on one side of the chip and all the processing transistors on the other side, thus providing close to 100% fill factor?
This could be the next step to eke out the maximum dynamic range from a sensor of a given size. Another approach might be to increase the well depth and use the microlens to precisely direct the light vertically down into the well, which I think is already being done towards the edges of the sensor.
There are no doubt lots of improvements that can be implemented before we hit the brick wall of 'the laws of physics'. However, I've often wondered to what extent diffraction degrades the preformance of microlenses. Is it significant ot not, and if so, at what size does it become significant?
[a href=\"index.php?act=findpost&pid=102708\"][{POST_SNAPBACK}][/a]
Amazing things can be done with microlenses as shown by the new Kodak chip used in the Leica M8, but all they can do is refocus the light that falls on them. They can't amplify light. I had thought about adding well depth to my discussion, but there are limits there too as shown in a recent thread comparing Kodak and Dalsa chips. If the well is too deep, edge performance suffers. Kodak circumvented some of this problem with microlenses for the Leica chip. According to Roger Clark, electron density per square micron of chip area has not improved much over the years, but new semiconductors, possibly not based on silicon, could change the situation dramatically. I'm not an engineer, but as I understand it, well depth is not necessarily literal. Increased dielectric properties could increase capacitance without actually changing the physical depth of the well. However, ISO performance is still needed in some areas.
Like you I'm an optimist too, Ray. Tremendous progress will be made in digital imaging, but the "laws" of physics won't be broken. I'm sure that advances will come in areas that I can't image (e.g superlenses, etc), and properties of which we are not currently aware will be utilized. Your thinking is more out of the box than mine, but if we look back at the last 40 years, progress has been made in ways that we or the science fiction writers did not imagine, but many things have remained relatively and unexpectedly unchanged.
Bill
-
`f
-
<a href="http://www.professionalontheweb.com/p/w/littleton+hair+salon/41571">Hair Salon in Littleton</a>
http://www.enthuse.me/wedding-packages-littleton
http://www.enthuse.me/littleton-hair-salon
http://ratemyarea.com/people/zerona-96949
http://plancast.com/littleton-hair-salon
https://colostate.academia.edu/hairsalonlittleton/Posts
http://www.professionalontheweb.com/p/w/littleton+hair+salon/41571
http://www.enthuse.me/denver-colorado#/show/links
http://littleton-hair-salons.weebly.com/
http://www.fotothing.com/littletonhairsalon/
https://cudenver.academia.edu/DenverColorado/Posts
http://littleton-hair-salon-denver.webnode.com/
http://moby.to/58a4bo
http://www.mobypicture.com/user/littletonsalon/view/17416168
http://juvederm.flavors.me/
-
I am very interested for having that 14-bit color. That's a huge thing imho.
[a href=\"index.php?act=findpost&pid=102890\"][{POST_SNAPBACK}][/a]
I don't think we should assume that 14-bit processing is in itself is a huge improvement, but rather it is indicative of improved shadow noise and dynamic range which requires the additional 2 bits for the capture of which.
-
I don't think we should assume that 14-bit processing is in itself is a huge improvement, but rather it is indicative of improved shadow noise and dynamic range which requires the additional 2 bits for the capture of which.
[a href=\"index.php?act=findpost&pid=102895\"][{POST_SNAPBACK}][/a]
14 bits isn't going to help a lot, unless read noise is reduced. Based on the samples, it doesn't really seem like there is any reduced noise in the MKIII. Hopefully, the production models will do better than the cameras that made the samples.
-
Video of the MkIII & 580 II:
www.photo-i.co.uk/News/Feb_07/Canon_spring.html
-
14 bits isn't going to help a lot, unless read noise is reduced. Based on the samples, it doesn't really seem like there is any reduced noise in the MKIII. Hopefully, the production models will do better than the cameras that made the samples.
[a href=\"index.php?act=findpost&pid=102899\"][{POST_SNAPBACK}][/a]
From IR:
"...Now that we've had some hands-on time with a late-rev prototype of the Canon EOS-1D Mark III, we're more impressed than ever. While the sample we've been working with is only a prototype, it's image quality and high-ISO noise levels are simply extraordinary. To our eyes, it looks like Canon has managed almost a full f-stop of noise improvement, the Mark III's ISO 6400 shots are only a little noisier than ISO 3200 ones from the Mark II N..."
Lots of sample images:
www.imaging-resource.com/PRODS/E1DMK3/E1DMK3A5.HTM
www.imaging-resource.com/PRODS/E1DMK3/E1DMK3A7.HTM
-
From IR:
"...Now that we've had some hands-on time with a late-rev prototype of the Canon EOS-1D Mark III, we're more impressed than ever. While the sample we've been working with is only a prototype, it's image quality and high-ISO noise levels are simply extraordinary. To our eyes, it looks like Canon has managed almost a full f-stop of noise improvement, the Mark III's ISO 6400 shots are only a little noisier than ISO 3200 ones from the Mark II N..."
Lots of sample images:
[a href=\"index.php?act=findpost&pid=102913\"][{POST_SNAPBACK}][/a]
The JPEGs at high ISO look less noisy, but they also look a little softer, so I don't know how much is due to NR in the JPEGs. I really need to see RAW files to come to a conclusion. The low-ISO images have very noisy shadows, IMO; I don't know how JPEG compression is affecting them. Improving high-ISO doesn't necessarily help on the low end, and Canon seems to be concentrated on the high end.
-
Well, do you have any information on what the fill factor of the Canon CMOS chips is? Even if the fill factor approaches 100 percent and the transistor area of the chip is markedly reduced, you still need a sufficient active pixel area to capture photons. The quantum efficiency could be doubled or tripled, but you still have to have a sufficient pixel size to control shot noise and maintain and dynamic range and sensitivity. These factors are summarized by Roger Clark (http://www.clarkvision.com/imagedetail/digital.sensor.performance.summary/). Do you have this additional information?
Bill
[a href=\"index.php?act=findpost&pid=102697\"][{POST_SNAPBACK}][/a]
Canon does not disclose such details, but companies like Sony, Kodak and Dalsa, who sell sensors directly, tell us more about their sensors. The new Sony sensor has photosites of about 12% the area of those in the 1DMkIII (2.5 vs 7.2 microns) and the well occupies about 30% of that area (effective fill factor is raised to about 50% by microlenses). So the transistors in that Sony CMOS sensor occupy an area of at most about 8% of the total area of a 1DMkIII photosite. And that is with "largish" 180nm process: the space occupied by transistors could potentially be reduced by a factor of nine by changing to the current state of the art 60nm process.
The possibilities for feature size reduction well below current levels has to be taken into account before predicting that we are at or near the limits of minimum viable photosite size. The paper by Wandell et discuss that factor?
Also, at high ISO speeds, wells are not being filled even at highlights; the sensor is effectively "underexposed". So well capacity is rather irrelevant to high ISO noise: what counts is how many photons the camera's lens can deliver to each photosite, the efficiency of the photosites at detecting those photons, and dark noise/read noise level in electrons.
Well size is relevant to maximum dynamic range possible when wells are almost filled at highlights, which is an aspect of performance at low ISO speeds.
-
... there are limits there too as shown in a recent thread comparing Kodak and Dalsa chips. If the well is too deep, edge performance suffers.
[a href=\"index.php?act=findpost&pid=102737\"][{POST_SNAPBACK}][/a]
The comparison shows the opposite when you skip the marketing hype and read the data sheets. The Kodak 39MP sensor with "narrower, deeper" wells of larger electron capacity has equally good off-perpendicular sensitivity as the Dalsa sensor with "wider, shallower" wells of smaller electron capacity.
-
According to Roger Clark, electron density per square micron of chip area has not improved much over the years
[a href=\"index.php?act=findpost&pid=102737\"][{POST_SNAPBACK}][/a]
According to actual data instead, there have been significant improvements over the last few years.
Kodak has increased the well capacity of its 6.8 micron pixel pitch FF CCD sensors 50%, from 40,000e in the sensor of the Olympus E-1 to 60,000e in recent models such as in the Leica M8 and H3D-39. That is, from 865e per square micron to 1300.
Also, the newly announced Sony CMOS sensor with 2.5 micron pitch has a well capacity of 10,000e (min), or 1600 per square micron. Quite impressive given the twin disadvantages of the lower fill factor of CMOS (30% I think Sony says, vs over 50% for the Kodak FF CCD's) and the expected lower fill factor of smaller photosites. The wells of the Sony sensor must be even "deeper" than the new, deeper than before Kodak ones.
-
According to actual data instead, there have been significant improvements over the last few years.
Kodak has increased the well capacity of its 6.8 micron pixel pitch FF CCD sensors 50%, from 40,000e in the sensor of the Olympus E-1 to 60,000e in recent models such as in the Leica M8 and H3D-39. That is, from 865e per square micron to 1300.
Also, the newly announced Sony CMOS sensor with 2.5 micron pitch has a well capacity of 10,000e (min), or 1600 per square micron. Quite impressive given the twin disadvantages of the lower fill factor of CMOS (30% I think Sony says, vs over 50% for the Kodak FF CCD's) and the expected lower fill factor of smaller photosites. The wells of the Sony sensor must be even "deeper" than the new, deeper than before Kodak ones.
[{POST_SNAPBACK}][/a] (http://index.php?act=findpost&pid=103041\")
Your figures are similar to what Roger reports: "For current technology of CCD and CMOS sensors, the full well capacities run about 800 to 1600 electrons per square micron. These values haven't changed much on over twenty years of sensor development."
Of course, you have to take fill factor into account and not simply consider pixel pitch. Fill factor for CCDs is typically 80-90% ([a href=\"http://www.dalsa.com/pi/products/DSC.asp]Dalsa[/url]) and is much lower for CMOS, around 30% for many designs, but improving as the transistor size is reduced by improved manufacturing techniques. We are not talking about an order of magnitude improvement here.
Bill
-
Well size is relevant to maximum dynamic range possible when wells are almost filled at highlights, which is an aspect of performance at low ISO speeds.
[a href=\"index.php?act=findpost&pid=103034\"][{POST_SNAPBACK}][/a]
And then, the lowest ISO needs to be amplified in such a way that the read noise is low, relative to max signal. If the RAW data only goes up to 2700, and the read noise is basically the same as ISO 100 in ADUs, then you're never going to see any improvement in DR; just better quality highlights and midtones.
-
And then, the lowest ISO needs to be amplified in such a way that the read noise is low, relative to max signal. If the RAW data only goes up to 2700, and the read noise is basically the same as ISO 100 in ADUs, then you're never going to see any improvement in DR; just better quality highlights and midtones.
[a href=\"index.php?act=findpost&pid=103098\"][{POST_SNAPBACK}][/a]
I think all of us who have taken the trouble to compare images at ISO 1600 from our 20D, 5D or 1D2 with the same scene underexposed by 4 stops at ISO 100, are impressed with the huge improvement in noise in the ISO 1600 shots, which stretches right across the tonal range but is particularly significant in the deep shadow, lower mid-tones and mid-tones. Owners of the new 1D3 should be able to compare ISO 3200 with a 5 stop underexposed ISO 100 shot and expect to see an even greater improvement, unless Canon have also improved shadow noise at ISO 100, in which case the degree of noise improvement might just be the same as that of the 1D2, just improved equally at all ISOs. I guess that remains to be seen.
However, I have to admit, as much as I am impressed with the results, I haven't much of a clue as to what processes are employed to achieve these outstanding results. Perhaps some of you clever chaps can enlighten me.
I have some vague understanding that the voltages generated at each photosite are amplified in the analog domain before becoming digitised. Such amplification of the signal allows read noise to be lower than it otherwise would be with an unamplfied (or less amplified) signal. (Don't know why this should be the case, though.)
I also have some vague understanding that the initial analog signal needs to be amplified because, in relation to full-well capacity, it's a much weaker signal than it could be.
What I don't understand at at all is, having established the technique of reducing noise through analog amplification (and no doubt through another 100 patented electronic tricks) why should well capacity limit the degree of amplification?
I have, for example, a shot at ISO 100. Full-well capacity is, say 50,000e which represents the highlights with ETTR exposure. I want to achieve the same level of noise in the shadows as I get with ISO 1600 whilst preserving the highlights and dynamic range that one expects at base ISO.
One could argue that boosting the analog signal in this situation would 'blow out' the highlights. Why should it? One photosite generates its maximum 50,000e signal and when amplified 4x becomes a 200,000e signal. Another photosite generates a 40,000e signal which, when amplified 4x becomes a 160,000e signal. The relationship and relativities are preserved.
Where's the problem? Is it possible that the interconnects cannot sustain such high voltages, or that excessive heat would degrade the results?
Can someone do me a favour and clarify this issue?
-
One could argue that boosting the analog signal in this situation would 'blow out' the highlights. Why should it? One photosite generates its maximum 50,000e signal and when amplified 4x becomes a 200,000e signal. Another photosite generates a 40,000e signal which, when amplified 4x becomes a 160,000e signal. The relationship and relativities are preserved.
Where's the problem? Is it possible that the interconnects cannot sustain such high voltages, or that excessive heat would degrade the results?
[a href=\"index.php?act=findpost&pid=103141\"][{POST_SNAPBACK}][/a]
There has to be a target voltage range for the ADC. Perhaps most of the read noise at low ISOs happens after the amplification at the photosites; before or in the ADC. IOW, perhaps part of the read noise has nothing whatsoever to do with amplification, and composes most of the total read noise at ISO 100, and only a fraction of it at ISO 1600.
-
One could argue that boosting the analog signal in this situation would 'blow out' the highlights. Why should it? One photosite generates its maximum 50,000e signal and when amplified 4x becomes a 200,000e signal. Another photosite generates a 40,000e signal which, when amplified 4x becomes a 160,000e signal. The relationship and relativities are preserved.
Where's the problem? Is it possible that the interconnects cannot sustain such high voltages, or that excessive heat would degrade the results?
Can someone do me a favour and clarify this issue?
[{POST_SNAPBACK}][/a] (http://index.php?act=findpost&pid=103141\")
The pre-amplifiers in the chip amplify voltage, not charge. 50,000 electrons in a photosite will produce a voltage according to the capacitance of the site, according to the formula V = Q / C, where V is voltage, Q the charge (1 coulomb = 6.24 × 10^18 electrons), and C is the capacitance. In a CMOS chip, this voltage is amplified by the transistors in the pixel, and the output of the pixel is voltage. This voltage is further amplified before being presented to the A/D converter as shown in this [a href=\"http://www.dalsa.com/shared/content/Photonics_Spectra_CCDvsCMOS_Litwiller.pdf]diagram[/url], figure 2.
At base ISO, the amplifier gain is usually set so that the full range of the ADC matches the single-pixel linear full well capacity of the chip. If one is shooting at 1/16 of base ISO (1600 for a camera with base ISO of 100), the well of the sensor fills only to 1/16 of full well. The amplifier gain is then increased 16 fold so that the output of the A/D converter will still be full scale. The number of electrons is not amplified, but rather the voltage. Dynamic range is reduced and noise increases according to photon counting statistics and read noise.
Most cameras allow a bit of headroom so that the ADU output for full well will be somewhat less than the full scale of the sensor (4095 for a 12 bit device) at base ISO. John is implying that the full well ADU of some Canons is only about 2700. In this case effective 11 bits (log[2700, base2]).
With my Nikon D200 with an exposure such that an 18% gray card gives a pixel value of about 118 with a gamma 2.2 space, the raw pixel value for the gray is 671 ADU and white paper gives 3558. Overflow occurs at 3986.
I hope this helps.
Bill
-
At base ISO, the amplifier gain is usually set so that the full range of the ADC matches the single-pixel linear full well capacity of the chip.
Well, thanks Bill for pointing out that the 'photon to electron' charge has to be converted to a voltage before analog amplification. I missed that point, but it doesn't really change the question, 'Why does the amplifier gain have to be set so the full range of the ADC matches full well capacity?'
If there's some noise advantage in amplifying the derived voltage from a charge just 1/16th and less, of full well capacity (as in an ISO 1600 shot), then why not use the same procedure to amplify the voltage derived from a full well signal. If necessary, such a signal could be brought back down to a lower level before recording to memory and hopefully leave some noise behind in the process.
Are the reasons just the impracticality of finding room on the sensor for perhaps the bigger and heavier duty components that might be required?
-
Well, thanks Bill for pointing out that the 'photon to electron' charge has to be converted to a voltage before analog amplification. I missed that point, but it doesn't really change the question, 'Why does the amplifier gain have to be set so the full range of the ADC matches full well capacity?'
[{POST_SNAPBACK}][/a] (http://index.php?act=findpost&pid=103197\")
Most current ADCs in common cameras have 12 bits resolution, but this goes up to 16 bits in high end units. As you know the new Canon uses 14 bits. If the maximal voltage is only half scale on the ADC, you have lost half of its resolution. When operating at higher than base ISO, the sensor wells are only partially filled, but still you want to use the full scale of the ADC. Thus, additional amplification is used. These considerations are explained further on [a href=\"http://en.wikipedia.org/wiki/Analog-to-digital_converter]Wikipedia[/url]
If you used a 16 bit ADC for a sensor with a full well of 50,000 electrons, each electron could be counted directly (gain = 1 ADU per electron), further amplification omitted, and you could adjust ISO in the raw converter. According to Roger Clark, it makes no sense to increase ISO on the camera above unity gain (ISO 1600 in the 5D, 800 on the D200, 1 ADU = 1 electron). John Sheehy feels better with some degree of oversampling. You can increase the ISO in the raw converter with no adverse effects in this case, just as we do with white balance. Since you like to think out of the box, another interesting idea would be to use an ADC with a log output. In this case information density would be spread evenly over the scale, and half the information would not be in the brightest f/stop as with current linear ADCs.
Bill
-
If you used a 16 bit ADC for a sensor with a full well of 50,000 electrons, each electron could be counted directly (gain = 1 ADU per electron),
Are you saying the problem is a matter of bit depth? If we want to start amplifying ISO 100 signals, then we might need perhaps 32 bit (per color) processing?
When operating at higher than base ISO, the sensor wells are only partially filled, but still you want to use the full scale of the ADC. Thus, additional amplification is used. These considerations are explained further on Wikipedia (http://en.wikipedia.org/wiki/Analog-to-digital_converter)
This Wikipedia article seems to be mainly about audio ADC converters. I'm having difficulty in seeing the relevance.
The noise advantage in Canon high ISO images seems to be due to analog amplifier gain, which is denied the ISO 100 signal.
If you want to use audio analogies, I'm reminded of the Dolby B NR system on my first cassette tape recorder many years ago. The signal prior to recording was boosted and the dynamic range compressed (to fit the range on the tape). The recorded signal was thus greater in relation to system noise. On playback, both the signal and 'tape hiss' were reduced in amplitude and the dynamic range of the original signal expanded.
However, I can't relate such a process to the recording of light signals. We have no method of amplifying light waves on this microscopic scale. I don't see how audio analogies are relevant.
-
Your figures are similar to what Roger reports: "For current technology of CCD and CMOS sensors, the full well capacities run about 800 to 1600 electrons per square micron.
[a href=\"index.php?act=findpost&pid=103064\"][{POST_SNAPBACK}][/a]
Can you give a lin to what Roger Clarke says? Is Clarke saying that "electron densities" of 1600e/sqmicron was available 20 years ago? That does not fit with what I see for even high end Full Frame type CCD's from just three years ago, where Kodak had about 800 with 6.8 micron pixels and 1100 with 9 micron pixels in MF sensors (size does help, as the lateral overflow drains of larger pixels take up a smaller fraction of total photosite area.) If sensors offered 1600 up to 20 years ago, they were probably special scientific ones without lateral overflow drains: absence of LOD's is good for very high DR scientific usage, but bad for blooming.
To repeat, what I see is not close to absence of progrs over 20 years, it is
- a 50% increase in well capacity in the same FF CCD pixel size over the last several years.
- Three years ago, 1100e/sqmicron in 9 micron FF CCD pixels and only 800 in 6.8 micron FF CCD pixels, implying considerably less that 800 in digicam size pixels, especially CMOS ones with their inherently lower true fill factor.
- Today, 1600 in 2.5 micron CMOS digicam pixels.
Those changes over just a few years, suggests a substantial improvement, at least in how small photosites can be and still maintain high levels of "electrons per unit area", probably a useful measure of highlight headroom. This seems relevant to the pessimistic claims that photosites (even DSLR photosites) have got about as small as "physical limits" allow them to be and still function well.
P. S. These numbers also suggest that reduced feature size is greatly reducing the disadvantage of CMOS and interline CCD sensors relative to FF CCDs in fill factor and electron well capacity for given pixel size, which might mark the beginning of the end of FF CCD. Maybe that is why Kodak has for the first time used interline CCD instead of FF CCD in a sensor for astro-photography and FourThirds cameras, the new KAI-10100.
-
However, I can't relate such a process to the recording of light signals. We have no method of amplifying light waves on this microscopic scale.
[a href=\"index.php?act=findpost&pid=103223\"][{POST_SNAPBACK}][/a]
You amplify the signal from the photosite, just as Dolby, tape bias and RIAA bias (for vinyl) amplify high frequency parts of the signal from the microphone. In each case, it is for protection against noise arising at later stages, not for reducing "shot noise" in the original detected signal.
Maybe the future of CMOS is amplifying on site so much that the voltage per electron is comfortably above the levels of subsequent noise sources, and than having an A/D convertor that can handle a high maximum input voltage and many bits: 16 or more. Well capacities of up to 65,536 electrons (above that of all current sensors except 9 micron pixel MF sensors) could in principle be counted "exactly" in 16 bits, allowing a fixed charge to voltage conversion ratio regardless of exposure index, so effectively a fixed sensitivity in the analogue domain. ISO speed would be applied only in conversion from raw.
-
Are you saying the problem is a matter of bit depth? If we want to start amplifying ISO 100 signals, then we might need perhaps 32 bit (per color) processing?
This Wikipedia article seems to be mainly about audio ADC converters. I'm having difficulty in seeing the relevance.
However, I can't relate such a process to the recording of light signals. We have no method of amplifying light waves on this microscopic scale. I don't see how audio analogies are relevant.
[a href=\"index.php?act=findpost&pid=103223\"][{POST_SNAPBACK}][/a]
The Wikipedia article does not even mention audio until well into the discussion. Digital signal processing is similar for both audio and video. Norman Koren (author of Imatest) got his start in audio engineering and has applied his expertise to digital photography. Much of the seminal work in signal processing got its start in Bell Laboratories and was related to sound.
The role of amplification prior to the ADC stage is to match the output voltage to the voltage range of the ADC. Bit depth has to do with resolution, the number of steps at which the highest voltage is counted. Bruce Fraser used an analogy to a staircase: dynamic range is the height of the staircase, whereas bit depth is the height of each step, that is the resolution.
The original Dolby system did not modulate sound directly, but the electrical analogue of the sound waves. I think the process is now done digitally. The same thing can be done with light. One can transform the spatial domain into the frequency domain.
Bill
-
If you used a 16 bit ADC for a sensor with a full well of 50,000 electrons, each electron could be counted directly (gain = 1 ADU per electron), further amplification omitted, and you could adjust ISO in the raw converter.
In order for that to work optimally, there would have to be virtually no read noise. Read noise is often measured in units of electrons, but it has absolutely nothing to do with electron charges. If you could compare the actual electrons in the well, and what you get after readout, the discrepancies would not be in whole, integer electron units. They would be in all kinds of whole-plus-fractional units of "electrons". So, counting electrons is not really possible, in the purest sense, with any kind of read noise. Probably about 0.3 electrons of read noise is what it would take to clearly discriminate numbers of electrons (given enough ADUs to discriminate). And then, you'd want slightly more than 1 ADU per electron - that gives an unevenly-gapped histogram, but at least the levels are all distinct, and an algorithm could clean up the histogram by using exactly 50,001 levels (0 to 50,000). When read noise is significant, you need even more ADUs to keep the digitized count as close as possible to the real electron count; truncating noise never decreases noise; truncating noise increases noise. Of course, these are subtle gains in extreme shadows.
A camera that literally counted exact numbers of photons would be a dream come true; all that would be left is shot noise, and shot noise is not really a noise except that we don't want to see it, but it is a physical reality of capturing light in bins; it is not a technological problem, except for the efficiency of collection.
According to Roger Clark, it makes no sense to increase ISO on the camera above unity gain (ISO 1600 in the 5D, 800 on the D200, 1 ADU = 1 electron). John Sheehy feels better with some degree of oversampling.
Not only do I; so does the noise, especially the horizontal line banding in Canon RAW data (other ISOs are normalized for ISO 100; the total noise is divided by ten):
(http://www.pbase.com/jps_photo/image/65737967/original.jpg)
These trends certainly suggest that a gain-based 3200 could easily have reduced noise, and decreases horizontal banding noise, especially.
You can increase the ISO in the raw converter with no adverse effects in this case, just as we do with white balance. Since you like to think out of the box, another interesting idea would be to use an ADC with a log output. In this case information density would be spread evenly over the scale, and half the information would not be in the brightest f/stop as with current linear ADCs.
[a href=\"index.php?act=findpost&pid=103214\"][{POST_SNAPBACK}][/a]
I don't think it's really an issue of how much "information" is in the stop; the real issue is where your signal is, relative to the noises. If you use the full top stop, read noise, relative to signal is only half what it would be if you exposed 1 stop lower, and shot noise (relative to signal), is only 71%. The noises are far more limiting, in practice, than "numbers of values" are.
As far as log output is concerned (I think you probably really mean gamma-adjusted; 0 has no log), the real issue is the read noise, and having a gamma-adjusted output from an ADC is not going to reduce the signal-to-read noise ratios, and the diodes or transistors used would probably add more noise of their own.
-
Bruce Fraser used an analogy to a staircase: dynamic range is the height of the staircase, whereas bit depth is the height of each step, that is the resolution.[a href=\"index.php?act=findpost&pid=103242\"][{POST_SNAPBACK}][/a]
That's not a particularly fitting analogy. The "height" is meaningless without a frame of reference. DR has various standards as to what is an acceptable S:N ratio, but basically, the idea is based upong the ratio of the highest recordable signal, to the lowest usable signal ("usable" open to interpretations and standards).
-
Can you give a lin to what Roger Clarke says? Is Clarke saying that "electron densities" of 1600e/sqmicron was available 20 years ago?
[{POST_SNAPBACK}][/a] (http://index.php?act=findpost&pid=103237\")
Here is [a href=\"http://www.clarkvision.com/imagedetail/does.pixel.size.matter/index.html] Roger's[/url] link. Look in the section Unity Gain Sensitivity. Roger is a very knowledgeable guy, but everything he says may not necessarily be true.
P. S. These numbers also suggest that reduced feature size is greatly reducing the disadvantage of CMOS and interline CCD sensors relative to FF CCDs in fill factor and electron well capacity for given pixel size, which might mark the beginning of the end of FF CCD. Maybe that is why Kodak has for the first time used interline CCD instead of FF CCD in a sensor for astro-photography and FourThirds cameras, the new KAI-10100.
[{POST_SNAPBACK}][/a] (http://index.php?act=findpost&pid=103237\")
That's a good point, but CMOS has its limitations also as described [a href=\"http://www.dalsa.com/shared/content/pdfs/CCD_vs_CMOS_Litwiller_2005.pdf]here.[/url] With deep submicron fabrication techniques, CMOS sensors develop problems in the analog portion of the chip. Below 0.25 μm supply voltages drop from 5 volt levels, imposing constraints on dynamic range. Below 0.35 μm, linearity of the transistor performance suffers. As Micheal pointed out in his sensor essay, all of the high end MF backs are CCD.
Bill
-
See Canon's full frame whitepaper http://www.robgalbraith.com/public_files/C...White_Paper.pdf (http://www.robgalbraith.com/public_files/Canon_Full-Frame_CMOS_White_Paper.pdf)
An explanation of Canon's noise reduction techniques is on page 17.
George Deliz
-
Thanks for the links and new information.
Roger is a very knowledgeable guy, but everything he says may not necessarily be true.
[a href=\"index.php?act=findpost&pid=103251\"][{POST_SNAPBACK}][/a]
Indeed, he just asserts that this 800 to 1600 has been about the same for 20 years, whereas my evidence shows significant improvements over a far shorter time period. More data from his site: Canon's CMOS DSLR sensors in his tables have densities around 1000, whereas the new smaller Sony CMOS improves this too 1600; again showing that considerable downsizing of DLSR photosite size is still possible while increasing electron density, thus potentially giving higher DR with smaller pixels.
... but CMOS has its limitations also ... With deep submicron fabrication techniques, CMOS sensors develop problems in the analog portion of the chip. Below 0.25 ?m supply voltages drop from 5 volt levels, imposing constraints on dynamic range. Below 0.35 ?m, linearity of the transistor performance suffers.
[a href=\"index.php?act=findpost&pid=103251\"][{POST_SNAPBACK}][/a]
Interesting; thanks. That does still leave prospects for interline CCD replacing FF (as in FourThirds with the E-400?) And even with those depth limits, that new Sony 1/1.8" 6MP 2.5 micron CMOS sensor has a higher electron density than any FF CCD I know of.
As Micheal pointed out in his sensor essay, all of the high end MF backs are CCD.
[a href=\"index.php?act=findpost&pid=103251\"][{POST_SNAPBACK}][/a]
Yes, but that is up till now: I was speculating about the future, and one of the dominant MF sensor makers, Kodak, has just moved interline CCD into territory previously monopolized by FF CCD. OK, that is still CCD not CMOS! I can see Live View (remotely on a computer monitor?) being useful with MF studio work, and then FF CCD is not an option.
-
I don't think it's really an issue of how much "information" is in the stop; the real issue is where your signal is, relative to the noises. If you use the full top stop, read noise, relative to signal is only half what it would be if you exposed 1 stop lower, and shot noise (relative to signal), is only 71%. The noises are far more limiting, in practice, than "numbers of values" are.
[{POST_SNAPBACK}][/a] (http://index.php?act=findpost&pid=103244\")
Many exponents of exposing to the right use the "information" in the stop as justification for the procedure, but I agree that the real justification is in the signal to noise ratio. The eye can only perceive a limited number of levels within the range of an f/stop.
As far as log output is concerned (I think you probably really mean gamma-adjusted; 0 has no log), the real issue is the read noise, and having a gamma-adjusted output from an ADC is not going to reduce the signal-to-read noise ratios, and the diodes or transistors used would probably add more noise of their own.
[a href=\"index.php?act=findpost&pid=103244\"][{POST_SNAPBACK}][/a]
Log ADCs are widely used in voice communications.
From [a href=\"http://en.wikipedia.org/wiki/Analog-to-digital_converter]Wikipedia[/url]
"For example, a voice signal has a Laplacian distribution. This means that the region around the lowest levels, near 0, carries more information than the regions with higher amplitudes. Because of this, logarithmic ADCs are very common in voice communication systems to increase the dynamic range of the representable values while retaining fine-granular fidelity in the low-amplitude region."
Such ADCs can not encode a value of zero, just as the progression of luminance's in the steps of the zone system can never represent 0: each step is half the preceeding. and true black is never reached.
Bill
-
That's a good point, but CMOS has its limitations also as described here. (http://www.dalsa.com/shared/content/pdfs/CCD_vs_CMOS_Litwiller_2005.pdf) With deep submicron fabrication techniques, CMOS sensors develop problems in the analog portion of the chip. Below 0.25 μm supply voltages drop from 5 volt levels, imposing constraints on dynamic range. Below 0.35 μm, linearity of the transistor performance suffers.
This is hardly a surprise. Because the gate width and distance between paths is smaller, you either need exotic materials where electrons won't leap across the gaps too often, or you'll need to reduce the core voltage of the circuit (conveniently combined with materials we might have thought were "exotic" a couple of decades ago).
A fundamental problem in circuit design today is the increased risk of errors, and the chip designers are performing miracles in assuring us that CPUs actually do what we expect them to, instead of behaving erratically.
So why not just keep the larger circuits with the higher voltage?
Well, higher voltage generally means a greater power consumption.
While I'm not familiar with the particular of the CMOS designs used by Canon and Sony (the Canon white paper isn't really detailed enough), it is conceivable that you could make a hybrid circuit in different processes for different tasks, but that is so complicated that I expect ongoing advances in "standard" CMOS engineering to be better, at least in the short term.
But that's just speculation, of course, and I'm not even in that particular industry.
-
You amplify the signal from the photosite, just as Dolby, tape bias and RIAA bias (for vinyl) amplify high frequency parts of the signal from the microphone. In each case, it is for protection against noise arising at later stages, not for reducing "shot noise" in the original detected signal.
[a href=\"index.php?act=findpost&pid=103239\"][{POST_SNAPBACK}][/a]
Agreed! There's some general principle that is vaguely similar here, but the application is quite different. As I understand it, Dolby is amplifying only those frequencies in the original signal that are in the same domain as the tape hiss generated on playback. After amplification and recording on the tape, the signal is brought back down to its original level (otherwise the music would sound odd) and in the process of which the tape hiss is consequently also reduced.
If one were to apply such a principle to the digital camera, the equivalent Dolby NR system would be looking at low level signals in an exposure at base ISO, amplifying only the low level signals from wells that generate a charge below a certain threshold. The fact that the voltages from only certain photosites had been amplified would be stored in temporary memory. Before recording the RAW file to flash card, such signals would be restored to their proper level, with consequent reduction of shadow noise.
Such an image at base ISO would then have similar low noise (with same exposure) as we see at high ISO, and at full ETTR exposure, at base ISO, dynamic range would be much expanded.
-
I'm going to amplify on this basic principle with a few demonstration shots. (Howard, do not criticise these images on the basis that they are processed for exhibition).
The dynamic range of DSLRs has been increased by the concept of ETTR (expose to the right). The DR of current DSLRs is now roughly equivalent that of to color film, but not as great as the best B&W film.
From previous comments, I know BJL thinks the DR of current DSLRs is sufficient.
The following images will show that it's not sufficient.
Whilst trekking recently in Nepal, I took a few shots to demonstrate the tremendous (monetary) value of accommodation, even though it was very poor by western standards. The following shots of hotel accommodation in the middle of the Nepalese hinterland, demonstrate the value you get for $6 a night with ensuite.
I tried to capture the 'room with a view' concept in the following shots.
Of course the DR of my 5D was not up to the task, as can be seen in the following shot.
[attachment=1940:attachment]
So what happens if I try my best to bring out the shadow detail?
[attachment=1941:attachment]
Well, clearly, that's an absolutely hopless shot. Nothing there that's interesting.
Supposing I take a shot that's right for the room.
[attachment=1942:attachment]
As you can see, I've lost the view.
Okay, so I blend 2 different exposures (as it so happens the differnece between an ISO 1600 exposure and an ISO 100 exposure.)
This is what I get.
[attachment=1943:attachment]
Whilst we're on the subject, here's the view from the ensuite. Blended images of course, but not a perfect blend. This would need some work before exhibition.
[attachment=1944:attachment]
Notice what a meticulously tidy person I am .
-
I'm going to amplify on this basic principle with a few demonstration shots. (Howard, do not criticise these images on the basis that they are processed for exhibition).
The dynamic range of DSLRs has been increased by the concept of ETTR (expose to the right). The DR of current DSLRs is now roughly equivalent that of to color film, but not as great as the best B&W film.
[{POST_SNAPBACK}][/a] (http://index.php?act=findpost&pid=103662\")
Ray,
I commend you on your digital blending, but disagree with your comparison of the dynamic range of digital (with a high end camera) to color film.
[a href=\"http://www.clarkvision.com/imagedetail/dynamicrange2/index.html]Roger Clark[/url] has done a detailed comparison of the dynamic range of a Canon 1D M2 with Fuji Velvia slide film and Kodak Gold 200 consumer negative film. Roger's test target had a metered luminance ratio of 1500:1, or about 10.6 f/stops.
The dynamic range of the digital was much better than the slide film and considerably better than the negative film. His transfer curves (figures 8a and 8b) are very instructive. Film, especially negative film, has high noise in the shadows, and this limits the floor of the dynamic range, where noise obscures useful shadow information.
As anyone who has used high speed color film and digital at high ISO knows, the advantage of digital is even more marked at high ISO, although this was not tested by Roger in that experiment.
Roger's experiment has been criticized in its use of a Polaroid Sprintscan 4000 in the tests. This scanner does not have the highest DMax, but Roger states that it was capable of capturing visible detail in the slides and negatives.
Bill
-
I commend you on your digital blending, but disagree with your comparison of the dynamic range of digital (with a high end camera) to color film.
[a href=\"index.php?act=findpost&pid=103743\"][{POST_SNAPBACK}][/a]
Bill, I see once again you are using Roger Clark as an appeal to authority .
I should have been more explicit. I meant that DSLRs have about the same dynamic range as color negative film; more than slide film but less than B&W film. My understanding is, the DR of slide film ranges from 4-6 stops, that of color film 7-9 stops and B&W film 9-11 stops.
I notice that Roger Clark used Royal Gold 200 in his tests. I don't know if this film has a reputation for a particularly high DR or just an average DR for an ISO 200 film. I get the impression that slow films would tend to have a better DR. However, I would not dispute that a modern DSLR has a higher DR than the average slide film. Nor would I dispute that that modern DSLRs do better than film in general at high ISO.
Extracting the full dynamic range from some negatives is a real challenge for both the scanner and the operator. Shadows on negative film can look so transparent one sometimes wonders if there's anything there at all. Yet with a scanner like the Nikon 8000ED which has analog gain, one can get surprising results by setting the gain to its minimum value (which reduces the time of the scan), then doing a second scan with a higher gain setting for the denser parts of the negative, then blend the 2 images.
-
Having attempted a google search on the dynamic range of color negative film, I'm beginning to have doubts if any DSLR can match the DR of color film.
There's a dynamic range test of Fuji Real 100 by someone at the University of Melbourne who gives it a theoretical DR of 15 stops. There's always going to be a subjective element as to just how useful the information might be in a particular stop at the extremes of the range. Some sources quote a theoretical DR of 20 stops for (presumably the best) color films. Digital sensors also have a theoretical DR, sometimes quoted by the manufacturer, but I've never seen figures as high as 15 stops.
The link to this experiment is http://www.path.unimelb.edu.au/~bernardk/t...hdri/index.html (http://www.path.unimelb.edu.au/~bernardk/tutorials/360/technical/hdri/index.html)
-
Agreed! There's some general principle that is vaguely similar here, but the application is quite different.
[a href=\"index.php?act=findpost&pid=103623\"][{POST_SNAPBACK}][/a]
The big difference is that Dolby and tape bias are trying to reduce high frequency noise (tape hiss) without increasing the total "bandwidth" used, so only high frequencies get extra amplification at the recording end, and extra de-amplification" at play-back, reducing the high frequency hiss. For digital photography, I envision simply amplifying everything enough to rise above the level of subsequent noise sources. The main barrier to this as far as I can tell is the dynamic range of the A/D convertor.
-
Bill, I see once again you are using Roger Clark as an appeal to authority .
[{POST_SNAPBACK}][/a] (http://index.php?act=findpost&pid=103756\")
If you look at Roger's [a href=\"http://www.clarkvision.com/rnc/index.html]biography[/url], it is indeed impressive, but I am appealing to Roger's data, not his eminence as a scientist. That is the beauty of the scientific method: it is based on data, not eminence. Roger's experimental setup is relatively simple, and his experiments could be replicated by any decent photographer. If you don't want to pay for ImagesPlus for analysis of linear raw data, you can use the freeware Iris (http://www.astrosurf.com/buil/us/iris/iris.htm) software.
As you may recall, two of your Aussie countrymen won the Nobel prize in Medicine or Physiology for discovering that stomach ulcers are often caused by a bacterial infection rather than primarily by oversecretion of acid. This theory was ridiculed by many "experts" who had made their name and often fortunes from the acid theory.
"The greatest obstacle to knowledge is not ignorance, it is the illusion of knowledge", quote (http://nobelprize.org/nobel_prizes/medicine/laureates/2005/marshall-slides.pdf) from Marshall's Nobel lecture, 2005. I think that this quotation also applies to photography: we must often adjust certain preconceived notions put forth by "experts". Perhaps Marshall's Aussie tendency of not bowing to dogma was instrumental in his (and his colleague's, Dr. Warren) discovery.
Bill
-
If you look at Roger's biography (http://www.clarkvision.com/rnc/index.html), it is indeed impressive, but I am appealing to Roger's data, not his eminence as a scientist. [a href=\"index.php?act=findpost&pid=103770\"][{POST_SNAPBACK}][/a]
Yes, I know you are, Bill. Just having a dig at you. Did you notice the smilie?
In these tests, Roger's data seems at odds with others and with my own experience. I don't know if it's due mainly to his choice of color negative film (Kodal Gold 200) or whether he could have done a better scanning job, or indeed whether he could have used a longer exposure. For best results with color negative film one also has to use a sort of ETTR principle. When I used to shoot with color negative film I often gave 1 to 1.5 EV greater than the exposure meter reading; that is for general scenes. Exposing similar scenes with my first DSLR, the D60, using the exposure meter without any compensation, would often result in irretrievably blown highlights, which I rarely experienced with color negative film despite giving a stop or 2 in excess of the meter reading.
-
For digital photography, I envision simply amplifying everything enough to rise above the level of subsequent noise sources. The main barrier to this as far as I can tell is the dynamic range of the A/D convertor.
[a href=\"index.php?act=findpost&pid=103769\"][{POST_SNAPBACK}][/a]
I'm not sure I understand why the dynamic range of the A/D converter should be a barrier. If all signals from all photosites are amplified by the same degree, the ratio between the lowest voltage and the highest voltage remains the same. However, the DR in the output should be greater because of improved shadow detail.
-
Having attempted a google search on the dynamic range of color negative film, I'm beginning to have doubts if any DSLR can match the DR of color film.
There's a dynamic range test of Fuji Real 100 by someone at the University of Melbourne who gives it a theoretical DR of 15 stops. There's always going to be a subjective element as to just how useful the information might be in a particular stop at the extremes of the range. Some sources quote a theoretical DR of 20 stops for (presumably the best) color films. Digital sensors also have a theoretical DR, sometimes quoted by the manufacturer, but I've never seen figures as high as 15 stops.
The link to this experiment is http://www.path.unimelb.edu.au/~bernardk/t...hdri/index.html (http://www.path.unimelb.edu.au/~bernardk/tutorials/360/technical/hdri/index.html)
[a href=\"index.php?act=findpost&pid=103765\"][{POST_SNAPBACK}][/a]
Let's be realistic here. Who as an amateur or professional photographer actually has the tools to get 15 stops out of color negative film? What sort of lab work would be necessary to do this?
Also, while digital sensors can give 10 stops (easy), or maybe 12 with RAW files, it is easy to in fact expand this range significantly in the situations where HDR processing is an option.
As a theoretical discussion, "# of stops" between color negatives and digital is a bit of a tired discussion... who actually shoots color negative film any more? I mean, people shot slide film for years for landscape and its range is severely limited compared to negative film.
-
With all this hooplah about the impressive dynamic range of today's DSLRs, it's rather interesting that Canon is one of the cooler "heads" (http://www.canon.com/technology/pdf/tech2006e.pdf):
The new CMOS sensor has been designed to
give greater depth to each pixel, allowing more
ample gradations, from highlighted to shadowed
portions of images. Each pixel can store more electric
charges, allowing a higher saturation point. As such,
the dynamic range of the CMOS sensor is on a par
with that of reversal film.
This is a full-frame 35mm high-resolution CMOS
sensor that performs on a par with 35mm film.
Yep, that's slide film, not negatives, and they probably mean colour film, not black and white.
-
I'm not sure I understand why the dynamic range of the A/D converter should be a barrier.
[a href=\"index.php?act=findpost&pid=103775\"][{POST_SNAPBACK}][/a]
Because my idea is to amplify the signal enough to measure differences down to one electron, so as to read even he low signal levels relevant to high ISO exposures, and to do this all the time, even when there are brightly lit photosites giving near maximum electron count too. Then with a well capacity of, say, 50,000 (5D), the A/D needs to cover a range of signal levels from 1 to 50,000: a DR of 50,000:1, needing 16 bit accuracy. Currently, different ISO setting either cannot count up to full well capacity (high ISO) or do not count very low signals accurately (low ISO).
-
Yes, I know you are, Bill. Just having a dig at you. Did you notice the smilie?
In these tests, Roger's data seems at odds with others and with my own experience. I don't know if it's due mainly to his choice of color negative film (Kodal Gold 200) or whether he could have done a better scanning job, or indeed whether he could have used a longer exposure. For best results with color negative film one also has to use a sort of ETTR principle. When I used to shoot with color negative film I often gave 1 to 1.5 EV greater than the exposure meter reading; that is for general scenes. Exposing similar scenes with my first DSLR, the D60, using the exposure meter without any compensation, would often result in irretrievably blown highlights, which I rarely experienced with color negative film despite giving a stop or 2 in excess of the meter reading.
[{POST_SNAPBACK}][/a] (http://index.php?act=findpost&pid=103773\")
In his experiments Roger did expose the medium to saturation, effectively exposing to the right. His saturation exposure for the negative film was +1 EV, which is less than I would have imagined, but that is what he got with the Kodak Gold 200. That film is no longer made, but in the [a href=\"http://www.kodak.com/global/en/professional/support/techPubs/e4040/e4040.pdf]data sheets[/url] for Kodak's newest Portra professional films, I note that the characteristic curve is linear up to a DMax of about 2.0 for green light; there is no shoulder.
When I used to scan film, I always preferred transparency film (Velvia, Provia, Kodachrome) to negative film, since I always found the grain to be excessive with negative film.
Bill
-
Let's be realistic here. Who as an amateur or professional photographer actually has the tools to get 15 stops out of color negative film? What sort of lab work would be necessary to do this?
Also, while digital sensors can give 10 stops (easy), or maybe 12 with RAW files, it is easy to in fact expand this range significantly in the situations where HDR processing is an option.
As a theoretical discussion, "# of stops" between color negatives and digital is a bit of a tired discussion... who actually shoots color negative film any more? I mean, people shot slide film for years for landscape and its range is severely limited compared to negative film.
[a href=\"index.php?act=findpost&pid=103777\"][{POST_SNAPBACK}][/a]
You've missed the point, CatOne. I'm not recommending a return to color negative film. I'm just replying to Bill's refutation of my statement that I believed current DSLRs have around the same DR capability as color negative film. Bill, quoting his favourite authority, Roger Clark, claims this is not so.
It's not entirely a dead issue. There appear to be still some photographers shooting film because they believe, rightly or wrongly, that negative film gives them wider latitude and DR (according to a google search).
-
Because my idea is to amplify the signal enough to measure differences down to one electron, so as to read even he low signal levels relevant to high ISO exposures, and to do this all the time, even when there are brightly lit photosites giving near maximum electron count too. Then with a well capacity of, say, 50,000 (5D), the A/D needs to cover a range of signal levels from 1 to 50,000: a DR of 50,000:1, needing 16 bit accuracy. Currently, different ISO setting either cannot count up to full well capacity (high ISO) or do not count very low signals accurately (low ISO).
[a href=\"index.php?act=findpost&pid=103803\"][{POST_SNAPBACK}][/a]
Fair enough! I imagine it's always better to have a greater DR capability in the components than may be actually required in practice.
I'd be happy if the quality of the lowest 2 stops or so was just improved to the point one could use them. I suspect the problem has more to do with miniaturising components that can handle the amplified voltages from photosites with a full charge. If this indeed is the problem, then selective amplification of just the low signals from certain sites might be a way around this. On the other hand, this approach would require more circuitry on the sensor and less room for the photodiode. We're between a rock and a hard place here.
-
In his experiments Roger did expose the medium to saturation, effectively exposing to the right. His saturation exposure for the negative film was +1 EV, which is less than I would have imagined, but that is what he got with the Kodak Gold 200. That film is no longer made, but in the data sheets (http://www.kodak.com/global/en/professional/support/techPubs/e4040/e4040.pdf) for Kodak's newest Portra professional films, I note that the characteristic curve is linear up to a DMax of about 2.0 for green light; there is no shoulder.
When I used to scan film, I always preferred transparency film (Velvia, Provia, Kodachrome) to negative film, since I always found the grain to be excessive with negative film.
Bill
[a href=\"index.php?act=findpost&pid=103834\"][{POST_SNAPBACK}][/a]
Of course, this is why it's very difficult to make general statements about film. You usually have to be specific. Which film? They've all got different characteristics. The situation is also complicated by the type of developer used.
Can we just say, Roger Clark has tested the DR of Royal Gold 200 and found it to be rather underwhelming. A test of one film type should not be cause for a general statement. My statement was of a general nature based on experience with a number of low ISO negative film types, usually ISO 100 but also Royal Gold 25 until it was discontinued. I've still got some rolls of Royal Gold 25 in the fridge, which I'm reluctant to throw away.
I'll also repeat, I was never able to get good detail in deep shadows (from color negative) without performing dual scans. I notice that Roger mentioned he would visually inspect the negative before scanning and that the scan would contain slightly more detail than he could see on the negative. I'd question this procedure.
-
Just to hammer the point home, I'll give some examples of my experiences which lead me to believe that color negative has no worse DR than a DSLR and possibly better in real, practical terms. Unfortunately, I have not compared the identical scenes, so I admit my methodology is flawed in this respect.
The following shot was taken with Kodak ISO 100 film. It was so long ago I can't remember if I used a tripod or relied upon IS. The general lack of 'tack sharpness' would suggest I didn't use a tripod.
[attachment=1948:attachment]
If I'd taken this shot with a 5D, I would expect to see unacceptable noise in the dark foreground when adjusting the images as follows.
[attachment=1949:attachment]
A few days after buying my 5D and 24-105mm lens as a package, I discovered on the net there was a known flare problem with the lens. The following shot was an attempt to discover the flare problem. I didn't succeed and have since never come across any flare problem that doesn't look like normal flare from any lens.
However, what I did discover in this experiment was a disappointing shadow performance of the 5D at ISO 100. At some point, the image becomes very degraded in a manner which I haven't seen with color negative film.
Below is the 5D shot I'm referring to. Conversion was minus 1.5EC to recover blown highlights. That wasn't possible. The brightest spots are completely blown. There's nothing blown in the negative scan. There's nothing that's 255,255, 255. There's nothing that has even a single 255, and there's nothing that has a 233, 233, 233, or 244, 244, 244, or 254, 254, 254 etc. I take that as meaning; no blown highlights in the negative scan.
The following shot was converted with shadows at zero, EC at minus 1.5 and contrast at minus 50.
[attachment=1950:attachment]
The adjusted image is going to leave some substantail areas dark, not only for esthetic reasons but also because shadow detail is crap.
[attachment=1951:attachment]
What's detail like in that dark band of foliage stretching across the middle right? Not too good.
[attachment=1952:attachment]
To summarise.
1. The scenes are different although similar in light intensities. Definitely a flaw in methodology there.
2. However, the film scan has no blown highlights. The 5D shot does, despite a minus 1.5EC correction.
PS. Forgot to mention. If anyone's interested, the film scan shot is of Cunningham's gap, not far from my studio, SE Queensland, Australia. The inferno on the right is probably where I'll go when I die. (Just joking! I kid myself I'm destined for heaven ).
-
FWIW
I'm not at all sure about theoretical aspects of this, but the last few years before switching to digital, I shot LF color negatives extensively (scanned thousands of them) in my business for clients that just wanted files. I prefered them because they clearly had a greater usable DR than any of the transparency films out there, though they were more work. I use Fuji films almost exclusively, NPS then 160 ProS and Provia and Velvia for magazines.
While transparencies scanned easier ,ie is it was easier to extract what was in the transparency vs. extracting the full potential of a neg. There are still issues of adequate profiles for color negatives because of the mask. All scanners are calibrated with transparencies (IT8) and the supplied profiles were always more accurate and consistent with transparencies as a result. Negative profiles always had to be tweaked much more than Trans. Negatives had more dynamic range potential but it was allot of work to extract it. Through experience we worked out how to do that. One of the big issues with CN was exposure. CN profiles are very exposure dependent. Meaning that if you tended to shoot a 160 film at 100 as I do, you virtually had to reinvent the canned profiles. Having said all that from a business point of view color negs were still more cost effective, because of saved film and processing costs, because we virtually did not have to bracket exposures with CN. Sharpening is more of an issue with CN as UM tends to sharpen and acentuate the grain-not an issue with trans., but as we were shooting 4x5 it did not matter much. The guru of scanning color negatives is Danny BurkDan Burk (http://www.dannyburk.com/drum_scanning_color_negative_film.htm) a Lf landscape photographer who is a big advocate of CN.
-
If I'd taken this shot with a 5D, I would expect to see unacceptable noise in the dark foreground when adjusting the images as follows.
A few days after buying my 5D and 24-105mm lens as a package, I discovered on the net there was a known flare problem with the lens. The following shot was an attempt to discover the flare problem. I didn't succeed and have since never come across any flare problem that doesn't look like normal flare from any lens.
However, what I did discover in this experiment was a disappointing shadow performance of the 5D at ISO 100. At some point, the image becomes very degraded in a manner which I haven't seen with color negative film.
The adjusted image is going to leave some substantail areas dark, not only for esthetic reasons but also because shadow detail is crap.
[a href=\"index.php?act=findpost&pid=103926\"][{POST_SNAPBACK}][/a]
This reminds me of problems I have with my Canon 5D and I must say this is one reason why I looked hard at MFD, but the weight/cost issue is a problem for my kind of work.
I also encountered that the 5D has sometimes problems with for example a sky with sunset where it can happen that the sky gets a staircase effect, not a smooth gradiation (yes I use Raw with DXO and tiff 16 Bit).
And yes the shadows can be crap, but I tend to open up the shadows of a digital file more, than the shadows of a scan, so maybe this is not a fair comparison.
Is this just the Canon 5D or a general digital problem ? Any solutions ?
Christian
-
This reminds me of problems I have with my Canon 5D and I must say this is one reason why I looked hard at MFD, but the weight/cost issue is a problem for my kind of work.
I also encountered that the 5D has sometimes problems with for example a sky with sunset where it can happen that the sky gets a staircase effect, not a smooth gradiation (yes I use Raw with DXO and tiff 16 Bit).
And yes the shadows can be crap, but I tend to open up the shadows of a digital file more, than the shadows of a scan, so maybe this is not a fair comparison.
Is this just the Canon 5D or a general digital problem ? Any solutions ?
Christian
[a href=\"index.php?act=findpost&pid=103946\"][{POST_SNAPBACK}][/a]
Never come across the staircase effect. Are you shooting RAW and converting into 16 bit ProPhoto?
The shadows can also be ugly with the 1Ds. If I'd given just half a stop less exposure to my above 5D example to reduce clipping of the highlights, the deep shadows would have been horrendous instead of plain awful.
Negative film has a broad shoulder. There's no sudden clipping as one overexposes. Likewise with the shadows. There seems to be a fairly even degradation of image quality where definition gradually becomes more and more obscured by grain. I guess this is why one can claim a 15 stop dynamic range for negative film. There's still some detail to be gleaned at each end of the spectrum.
-
Perhaps we should be talking about this in the past tense. Negative film used to have a broad shoulder.
-
My statement was of a general nature based on experience with a number of low ISO negative film types, usually ISO 100 but also Royal Gold 25 until it was discontinued. I've still got some rolls of Royal Gold 25 in the fridge, which I'm reluctant to throw away.
A friend of mine adored the clean images he got with Royal Gold 25, and was pissed when it was discontinued.
However, he's (so far) satisfied with the image quality of his 1D MkII, so he apparently wasn't enjoying Royal Gold 25 for its dynamic range as much as the generally clean images.
-
A friend of mine adored the clean images he got with Royal Gold 25, and was pissed when it was discontinued.
However, he's (so far) satisfied with the image quality of his 1D MkII, so he apparently wasn't enjoying Royal Gold 25 for its dynamic range as much as the generally clean images.
[a href=\"index.php?act=findpost&pid=103964\"][{POST_SNAPBACK}][/a]
Royal Gold 25 was my favourite film before I bought my first DSLR, the D60. I was also dismayed when the film was discontinued, so I bought a few rolls whlist I could still get them. That's why I've still got a few in the fridge.
I was not only impressed with the fine grain, but there was a quality about the color, hue and saturation that pleased me greatly. If I was into conspiracy theories, I would even suggest that Kodak discontinued this film in order to remove competition to its digital cameras.
-
For some strange reason, Ektar 25, the slide film with presumably even finer grain than Royal Gold 25, was discontinued first. A short time after Kodak issued a sampler Photo CD disc with some Ektar 25 shots, I noticed at an exhibition in Brisbane a Kodak 6mp DSLR (Nikon body) for the trivial sum of A$40,000.
Of course, being a rational sort of person, my mind automatically stripped off a zero and I remember walking around looking at the rest of the exhibits thinking I might soon be able to afford one of those cameras.
The fact is, when some years later I saw sample images on Kodak's web site from their latest 6mp DSLR, they didn't seem (in my opinion) anywhere near the quality of these 18mb scans (now over 15 years old) on their sampler Photo CD disc.
Here's one which I like in particular. Taken by Bob Clemens, unfortunately.
[attachment=1954:attachment]
The texture of the skin is quite remarkable as can be seen in this 100% crop.
[attachment=1955:attachment]
Not bad for an 18mb scan, eh!?
-
You've missed the point, CatOne. I'm not recommending a return to color negative film. I'm just replying to Bill's refutation of my statement that I believed current DSLRs have around the same DR capability as color negative film. Bill, quoting his favourite authority, Roger Clark, claims this is not so.
It's not entirely a dead issue. There appear to be still some photographers shooting film because they believe, rightly or wrongly, that negative film gives them wider latitude and DR (according to a google search).
[a href=\"index.php?act=findpost&pid=103886\"][{POST_SNAPBACK}][/a]
Perhaps it's not entirely a dead issue, but those photographers who shoot negative film because digital doesn't have the same DR must enjoy the sand in their ears when they remove their head from the sand.
Practically, the solutions for shots that require 15 stops (lo, let's say 20 stops) of DR are rather straightforward, including:
* Don't take the shot in the first place... it may be uninteresting
* Use a ND grad filter, if you have one, to compress dynamic range
* Take the shot twice with digital, and composite it (as you showed in your example above)
#3 takes someone with working knowledge of Photoshop about 2 minutes to do, to get a fine result (one that looks substantially more realistic than your composites from the hotel room). To say that film with its wider shoulder gives a better DR is really a silly argument, because you are artificially constraining what's allowed simply to make film "win" the judgement. The outcome is predicating the test and the "rules" to justify a certain conclusion.
Plus, if the 1D III (that is what this thread is about, after all), truly does have 1 or 2 stops more DR than the 5D then perhaps the shadow details would be better. Still, in a shot with > 8 stops of DR, if you're going to pull the shadows from zone 2 to zone 4, I'd argue the results would be better with a composite.
-
...
Not bad for an 18mb scan, eh!?
[a href=\"index.php?act=findpost&pid=103974\"][{POST_SNAPBACK}][/a]
I'd argue it could use some color work, or perhaps the converse is that I don't like the palette that films of 2 decades ago provided, as I assume that's the color they intended it to be
-
Of course, this is why it's very difficult to make general statements about film. You usually have to be specific. Which film? They've all got different characteristics. The situation is also complicated by the type of developer used.
Can we just say, Roger Clark has tested the DR of Royal Gold 200 and found it to be rather underwhelming. A test of one film type should not be cause for a general statement. My statement was of a general nature based on experience with a number of low ISO negative film types, usually ISO 100 but also Royal Gold 25 until it was discontinued. I've still got some rolls of Royal Gold 25 in the fridge, which I'm reluctant to throw away.
I'll also repeat, I was never able to get good detail in deep shadows (from color negative) without performing dual scans. I notice that Roger mentioned he would visually inspect the negative before scanning and that the scan would contain slightly more detail than he could see on the negative. I'd question this procedure.
[{POST_SNAPBACK}][/a] (http://index.php?act=findpost&pid=103896\")
Roger's scanning methods are not well documented, but he did specify that they were 12 bit. The dynamic range noise floor for Kodak Gold was high due to grain. The DR noise floor for Royal Gold 25 could conceivably be better, but we have no data.
We gan get some information from the characteristic curve of the referenced films. I will consider only the green response.
Royal Gold 25
[attachment=1958:attachment]
The log exposure range is -1.84 to +1.6, for a total range of 3.44 logs. The luminance ratio would be 10^3.44 or 2754:1, or about 11.4 f/stops. Therefore, the maximal DR of this film is 2754:1, not considering noise, which would lower the effective DR. Of course, you could claim that Kodak could have extended the exposure scale to capture DR not shown in the characteristic curve. However, manufacturers do not typically understate the merits of their product, and the limits of the toe and shoulder are apparent in the published curve.
Gold 200
[attachment=1959:attachment]
The log exposure range is -2.9 to +0.8, for a total range of 3.7 logs or 5011:1, 12.3 f/stops not taking noise into consideration. This DR is actually better than Royal Gold 25, but would be degraded by noise in practice.
According to Roger's [a href=\"http://www.clarkvision.com/imagedetail/evaluation-1d2/index.html]Table 1a[/url], the DR of the Canon D1 M1 is 3190:1, with the noise floor 1 SD above the read noise. Looking at Roger's Figure 10 (http://www.clarkvision.com/imagedetail/dynamicrange2/index.html), we see that the noise of the Canon 1D M2 is much better in the shadows of the film. You can say Roger's noise figures for the film are way off, but from the characteristic curve of the film, the DR can be no greater than 5011:1. Also note that Roger's response curve is similar to that shown in the Kodak data sheet.
I don't think the DR of Royal Gold 25 is quite up to your fond memories of it.
Bill
-
Just to hammer the point home, I'll give some examples of my experiences which lead me to believe that color negative has no worse DR than a DSLR and possibly better in real, practical terms. Unfortunately, I have not compared the identical scenes, so I admit my methodology is flawed in this respect.
[a href=\"index.php?act=findpost&pid=103926\"][{POST_SNAPBACK}][/a]
I suspect that the dynamic range of the scene in your 5D photo was most likely considerably higher than that of your film shot, and you have identified the flaw in your comparison.
Actually, the shadow noise characteristics of the 5D are far superior to film as brought out previously in this thread.
Bill
-
I'd argue it could use some color work, or perhaps the converse is that I don't like the palette that films of 2 decades ago provided, as I assume that's the color they intended it to be
[a href=\"index.php?act=findpost&pid=104007\"][{POST_SNAPBACK}][/a]
As I recall, that PhotoCD image was used by Bruce Fraser in one of his books to illustrate how to remove a blue cast in the skin tones.
Bill
-
Having attempted a google search on the dynamic range of color negative film, I'm beginning to have doubts if any DSLR can match the DR of color film.
There's a dynamic range test of Fuji Real 100 by someone at the University of Melbourne who gives it a theoretical DR of 15 stops. There's always going to be a subjective element as to just how useful the information might be in a particular stop at the extremes of the range. Some sources quote a theoretical DR of 20 stops for (presumably the best) color films. Digital sensors also have a theoretical DR, sometimes quoted by the manufacturer, but I've never seen figures as high as 15 stops.
The link to this experiment is http://www.path.unimelb.edu.au/~bernardk/t...hdri/index.html (http://l)
[a href=\"index.php?act=findpost&pid=103765\"][{POST_SNAPBACK}][/a]
The experiment is interesting, but I think that a flaw in the author's method is that he is detecting very small changes in the response in the shoulder of the curve by averaging hundreds of pixels in his large tone patches in order to detect a significant change in pixel value.
For a high resolution picture, we are interested in changes of density over a much smaller interval (as "my favorite author" pointed out in his post). I would be interested in some real high resolution images from this shoulder area to see if this "dynamic range" is useful. Roger's analysis of the film was mainly concerned with shadow noise limiting the effective DR floor. He did state that if he measured the signal over a large area of the target so that many film grains could be averaged, the DR floor could be extended, but that small detail would be lost in the noise.
Bill
-
For some strange reason, Ektar 25, the slide film with presumably even finer grain than Royal Gold 25, was discontinued first. A short time after Kodak issued a sampler Photo CD disc with some Ektar 25 shots, I noticed at an exhibition in Brisbane a Kodak 6mp DSLR (Nikon body) for the trivial sum of A$40,000.
Of course, being a rational sort of person, my mind automatically stripped off a zero and I remember walking around looking at the rest of the exhibits thinking I might soon be able to afford one of those cameras.
The fact is, when some years later I saw sample images on Kodak's web site from their latest 6mp DSLR, they didn't seem (in my opinion) anywhere near the quality of these 18mb scans (now over 15 years old) on their sampler Photo CD disc.
Here's one which I like in particular. Taken by Bob Clemens, unfortunately.
The texture of the skin is quite remarkable as can be seen in this 100% crop.
Not bad for an 18mb scan, eh!?
[{POST_SNAPBACK}][/a] (http://index.php?act=findpost&pid=103974\")
Ray,
In my Google search I came across this [a href=\"http://www.debevec.org/Research/HDR/debevec-siggraph97.pdf]paper[/url] (figure 8) which contains an illustration of the Stanford University Memorial Chapel from a PhotoCD disc of a print film shot (film unstated) that has a very high dynamic range. I think I will have to rethink my previous posts, but I thought I would let you know about this.
By the way, what is wrong with Bob Clemens?
Bill
-
Practically, the solutions for shots that require 15 stops (lo, let's say 20 stops) of DR are rather straightforward, including:
* Don't take the shot in the first place... it may be uninteresting
* Use a ND grad filter, if you have one, to compress dynamic range
* Take the shot twice with digital, and composite it (as you showed in your example above)
[a href=\"index.php?act=findpost&pid=104006\"][{POST_SNAPBACK}][/a]
CatOne,
You don't have to convince me of the benefits of shooting digital. I'm aware of the basic techniques and possibilities of blending images to increase dynamic range, even though I might not be as clever as you in knocking up a perfect blend in 2 minutes of Photoshop work.
However, I'm not aware of any technique of getting acceptably good registration of hand-held bracketed shots. The automatic alignment feature in Photoshop's 'merge to HDR' seems less effective than manually repositioning the layers.
There are many situations when using a tripod is not practical. You might need to take a shot in a hurry and don't have time to set up the tripod. You might be in a situation where you are simply not carrying a tripod for whatever reason, or you might be in a situation where tripods are banned (as well as use of flash) as in many old churches and museums in Italy. Split ND filters are of limited use. They generally require something like a horizontal sky line stretching across the image or similar division.
However good the DR of modern DSLRs is, at base ISO it doesn't seem to have increased much during the past few years. The improvement seems to have been directed mainly at high ISO performance. If the 1D3 can manage a real additional stop of dynamic range at ISO 100, that'll be just great.
-
However good the DR of modern DSLRs is, at base ISO it doesn't seem to have increased much during the past few years. The improvement seems to have been directed mainly at high ISO performance. If the 1D3 can manage a real additional stop of dynamic range at ISO 100, that'll be just great.
[a href=\"index.php?act=findpost&pid=104202\"][{POST_SNAPBACK}][/a]
I wouldn't put too much hope in that. The blackframe read noise of a mkIII 14-bit RAW at ISO 100 is 4.88 ADU. Translated to 12-bit, that's 1.22, a modest gain over the ~1.26 of the mkII (and perhaps just a camera-specific thing; the gain could vary a little from copy to copy). The mkII data goes up to about 3711 on the clipped specimens I've seen, and the blackpoint is 128, so there are about 3583 12-bit levels. The mkIII RAWs I have clip at about 15280 and have a blackpoint of 1024, so they have about 14,256 14-bit levels, or about 3,564 12-bit levels. Since ISO 100 doesn't even use close to full well, it should be linear right up to clipping, with no hidden extra highlights.
Now, that's DR by the more liberal definition of max_signal:noise_floor. In the brighter shadows and midtones, if the camera is capturing more photons at the same absolute exposure, then you may very well see a slight improvement there, but note that it would take a collection of *4x* as many photons to halve shot noise at any arbitrary tonal level. 4x as many as the mkII would most likely be more than 100% of the photons available.
I am a skeptic by nature, and that is why I don't jump up and down over company announcements. They rarely materialize in the way they are announced. The increased DR that Canon talks about may be nothing more than "better" JPEG NR at high ISOs, conservative metering (leaving nmore headroom, but giving more noise), or the 14-bit data (which is working with too much noise to be of full value).
The 14-bit data may help indirectly, as it will force ACR to work on the RAWs in a deeper space than the 12-bit cameras, which may improve the banding removal. If the line banding in previous cameras was caused by the ADCs, then perhaps this new line of ADCs will reduce banding.
-
In my Google search I came across this paper (http://www.debevec.org/Research/HDR/debevec-siggraph97.pdf) (figure 8) which contains an illustration of the Stanford University Memorial Chapel from a PhotoCD disc of a print film shot (film unstated) that has a very high dynamic range. I think I will have to rethink my previous posts, but I thought I would let you know about this.
By the way, what is wrong with Bob Clemens?
[a href=\"index.php?act=findpost&pid=104053\"][{POST_SNAPBACK}][/a]
Bill,
Now that's what I'd call a technical article, but I'm not sure I want to go there. Too much mathematics .
It's not entirely clear to me that the variations on the Chapel are just from one shot. Most of the article seems to be about blending multiple shots. However, that's exactly the situation which a DSLR cannot handle in a single shot; light pouring through a stained glass window in a church. One either sacrifices some highlights for the sake of reasonably clean shadows, or one exposes for the stained glass and accepts overly dark shadows. At least that's my experience.
I spent some time today reviewing such shots from my trip to Italy (where tripods and flash units are mostly banned), and got a few surprises. The high ISO shots seemed to have better shadow detail than the ISO 100 shots, taken in similar situations, but not identical situations, so I'm afraid it's not a scientific comparison. My general approach was, if I could get a reasonably fast shutter speed at ISO 100, I'd use it. If I couldn't, I'd increase ISO. This would tend to imply that the ISO 100 shots would generally be taken in better lighting conditions, so I'm at a loss to explain why shadow detail should be so bad.
Below are a few screen shots of the conversions in ACR, each followed by the processed image which attempts to bring out the shadows. None of the images have had any noise reduction applied apart from sometimes a 'luminance smoothing' of 25 in ACR.
[attachment=1965:attachment] [attachment=1966:attachment] [attachment=1967:attachment] [attachment=1968:attachment] [attachment=1969:attachment] [attachment=1970:attachment]
As you can see, I don't think shadows could be much worse than this. It's true that I could have given slightly more exposure to some of these ISO 100 shots, but so I could have with some of the following shots ranging from ISO 800 to 1600.
[attachment=1971:attachment] [attachment=1972:attachment] [attachment=1973:attachment] [attachment=1974:attachment] [attachment=1975:attachment] [attachment=1976:attachment] [attachment=1977:attachment] [attachment=1978:attachment]
What's wrong with Bob Clemens? I don't know him. It's just unfortunate that it was him behind the camera and not me .
-
It's not entirely clear to me that the variations on the Chapel are just from one shot. Most of the article seems to be about blending multiple shots. However, that's exactly the situation which a DSLR cannot handle in a single shot; light pouring through a stained glass window in a church. One either sacrifices some highlights for the sake of reasonably clean shadows, or one exposes for the stained glass and accepts overly dark shadows. At least that's my experience.
[a href=\"index.php?act=findpost&pid=104238\"][{POST_SNAPBACK}][/a]
Ray,
On re-reading that article, I think that you are correct. Figure 8a was a straight shot of the chapel, and the remaining illustrations were rendered from the HDR radiance map using blended exposures. The dynamic range of that scene was 100,000:1. Fortunately, there is little need for digital photographers to wade through the math employed in the paper, which is directed largely to undo the non-linearities of film photography.
I agree with your assessment of exposure. There is no way to capture such a scene in one shot with current digital cameras.
I spent some time today reviewing such shots from my trip to Italy (where tripods and flash units are mostly banned), and got a few surprises. The high ISO shots seemed to have better shadow detail than the ISO 100 shots, taken in similar situations, but not identical situations, so I'm afraid it's not a scientific comparison. My general approach was, if I could get a reasonably fast shutter speed at ISO 100, I'd use it. If I couldn't, I'd increase ISO. This would tend to imply that the ISO 100 shots would generally be taken in better lighting conditions, so I'm at a loss to explain why shadow detail should be so bad.
[a href=\"index.php?act=findpost&pid=104238\"][{POST_SNAPBACK}][/a]
Your explanation of the exposure factors seems reasonable, but it might be that the illumination inside the church of the first picture at ISO 100 with particularly bad shadow noise and banding was very low. The only way to know for sure would be to take spot readings from the stained glass window and the interior of the church and determine the contrast ratio.
In post-Christian Italy were there any locals worshiping in those churches or was everyone a tourist?
Bill
-
I wouldn't put too much hope in that. The blackframe read noise of a mkIII 14-bit RAW at ISO 100 is 4.88 ADU. Translated to 12-bit, that's 1.22, a modest gain over the ~1.26 of the mkII (and perhaps just a camera-specific thing; the gain could vary a little from copy to copy). The mkII data goes up to about 3711 on the clipped specimens I've seen, and the blackpoint is 128, so there are about 3583 12-bit levels. The mkIII RAWs I have clip at about 15280 and have a blackpoint of 1024, so they have about 14,256 14-bit levels, or about 3,564 12-bit levels. Since ISO 100 doesn't even use close to full well, it should be linear right up to clipping, with no hidden extra highlights.
[{POST_SNAPBACK}][/a] (http://index.php?act=findpost&pid=104216\")
John,
I notice that the comparison shots at Imaging Resource, [a href=\"http://www.imaging-resource.com/PRODS/E1DMK3/E1DMK3A5.HTM]http://www.imaging-resource.com/PRODS/E1DMK3/E1DMK3A5.HTM[/url] , show the the 1D3 at ISO 6400 as having virtually the same performance as the 1D2 at ISO 3200. With both cameras at ISO 3200, the 1D3 seems noticeably cleaner. With both cameras at ISO 1600, the differences seem reduced but the 1D3 still marginally better. I imagine if we could see comparisons right down the ISO scale to ISO 100, the differences would gradually reduce to the point where at ISO 100 there would be no noticeable difference except marginally greater resolution on the line charts.
If this is so, it confirms my impression that the DR improvements are directed at high ISO performance only.
Nevertheless, it looks as though Canon have provided a real ISO 3200 in this camera, which is better than using the same exposure at ISO 1600.
Also, I'm wondering what the implications of the 10 frames per second speed might be for hand-held bracketed shots. Clearly, there has to be a minimum shutter speed for this, but I don't recall seeing it mentioned. For example, 10 exposures at 1/20th sec would take up 1/2 a sec, allowing a maximum time of just 1/20th sec to reset the sensor for the next exposure.
I wonder if it would be possible to bracket exposures at high ISO, using IS, and get shots for blending which are effectively as good as tripod shots?
-
Your explanation of the exposure factors seems reasonable, but it might be that the illumination inside the church of the first picture at ISO 100 with particularly bad shadow noise and banding was very low.
That has to be the explanation. It's just curious that whenever I decided to use ISO 100 for this type of shot, the dynamic range of the scene appears to have been much greater than those occasions when the lighting was so bad I needed to use a high ISO.
In post-Christian Italy were there any locals worshiping in those churches or was everyone a tourist?
I could count on one hand the number of occasions a service was being held at the time I visited a church. Most of the time, just masses of tourists swirling around. Pretty similar to Angkor Wat in that respect.
We have to accept that Italy is the greatest repository of art in the world, by far I would think.
-
Also, I'm wondering what the implications of the 10 frames per second speed might be for hand-held bracketed shots. Clearly, there has to be a minimum shutter speed for this, but I don't recall seeing it mentioned. For example, 10 exposures at 1/20th sec would take up 1/2 a sec, allowing a maximum time of just 1/20th sec to reset the sensor for the next exposure.
It's not just a matter of resetting the sensor, the mirror and shutter need their time, too.
See page 61 of the white paper:
Continuous Shooting Speed: Approx. 10 fps (at a shutter speed of 1/500 sec. or faster
in all recording modes)
-
It's not just a matter of resetting the sensor, the mirror and shutter need their time, too.
See page 61 of the white paper:
Continuous Shooting Speed: Approx. 10 fps (at a shutter speed of 1/500 sec. or faster
in all recording modes)
[a href=\"index.php?act=findpost&pid=104380\"][{POST_SNAPBACK}][/a]
In that case the 1D3 is not going to be fast enough for handheld bracketed shots for blending purposes. The interval between, say 1/500th and 1/2000th at ISO 1600 is going to be just slightly shorter than 1/9th sec. Too much scope for camera shake I'm afraid.
-
As far as log output is concerned (I think you probably really mean gamma-adjusted; 0 has no log), the real issue is the read noise, and having a gamma-adjusted output from an ADC is not going to reduce the signal-to-read noise ratios, and the diodes or transistors used would probably add more noise of their own.
[{POST_SNAPBACK}][/a] (http://index.php?act=findpost&pid=103244\")
Actually, a gamma adjusted encoding is not good for HDR (high dynamic range) images because the slope of the curve becomes infinite towards zero luminance, and the steps at low luminance are very large, leading to posterization. This is why the sRGB curve has a linear segment at low luminance. The linearly encoded raw file is a limited form of HDR encoding, but it wastes bits at high luminances and requires a large number of bits to represent the data, hence Canon's upping the bit depth of the 1D M3 to 14 bits from 12--hopefully, they know what they are doing. A log encoding would be more efficient and has proportionally equal encoding steps throughout its range, but it can't represent zero luminance. However, at very low luminances the digital images contain little information due to noise and a encoding of these values may not be warranted, since they are often clipped in the final output. Floating point encoding has properties similar to log encoding.
As [a href=\"http://www.anyhere.com/gward/hdrenc/hdr_encodings.html]Greg Ward[/url] notes on his web site, for most of the history of photography, we have used HDR encoding with negative film, which has a log response. This paper is a good source of information for various types of encoding, and Greg discusses the factors that are mentioned above. For example, sRGB has a useful log base 10 DR of 1.6 or 40:1.
-
In that case the 1D3 is not going to be fast enough for handheld bracketed shots for blending purposes. The interval between, say 1/500th and 1/2000th at ISO 1600 is going to be just slightly shorter than 1/9th sec. Too much scope for camera shake I'm afraid.
[a href=\"index.php?act=findpost&pid=104393\"][{POST_SNAPBACK}][/a]
If you had an accurate way to register the images with sophisticated software, perhaps blending would be possible with hand held shots. In Debevec's previously mentioned paper, he derived the irrradiance curve for the Memorial Chapel from 16 photographs processed from PhotoCDs, which do not scan precisely the same image areas each time around. He used normalized correlation to obtain subpixel registration among the various images.
Bill
-
If you had an accurate way to register the images with sophisticated software, perhaps blending would be possible with hand held shots. In Debevec's previously mentioned paper, he derived the irrradiance curve for the Memorial Chapel from 16 photographs processed from PhotoCDs, which do not scan precisely the same image areas each time around. He used normalized correlation to obtain subpixel registration among the various images.
[a href=\"index.php?act=findpost&pid=104405\"][{POST_SNAPBACK}][/a]
Bill,
I have no doubt that a program could be written to handle this. Perhaps one already exists, but I haven't come across it. However, I think there's a difference between images that are merely misaligned on an actual 2-dimensional plane (as in scanning) and images that are misaligned due to 3-dimensional camera shake, which might consist of any combination of tilting, twisting, rotating, back/forward and sidewards movement.
Whever I've tried manually aligning layers for blending (from handheld shots) at high magnification in order to get pixel accuracy, I've failed to get all parts of the image perfectly aligned simultaneously.
-
In that case the 1D3 is not going to be fast enough for handheld bracketed shots for blending purposes. The interval between, say 1/500th and 1/2000th at ISO 1600 is going to be just slightly shorter than 1/9th sec. Too much scope for camera shake I'm afraid.
I don't understand why you appear so surprised.
Nobody seems to have claimed that the 10 fps performance of the 1D Mk III has been any quicker than 10 fps, and it seems self-evident that these must be at least close to evenly spaced across a second.
It doesn't matter if you're at ISO 1600, or if the shutter time is 1/500 or 1/1000000 of a second.
-
I don't understand why you appear so surprised.
Nobody seems to have claimed that the 10 fps performance of the 1D Mk III has been any quicker than 10 fps, and it seems self-evident that these must be at least close to evenly spaced across a second.
It doesn't matter if you're at ISO 1600, or if the shutter time is 1/500 or 1/1000000 of a second.
[a href=\"index.php?act=findpost&pid=104648\"][{POST_SNAPBACK}][/a]
I'm not really surprised, but I see there's a point of logic here that escaped me when I raised the question. If the camera were able to shoot 10 fps at 1/20th second exposure, then it would surely be able to manage more than that at 1/500th, which it can't as you point out.
-
I'm not really surprised, but I see there's a point of logic here that escaped me when I raised the question. If the camera were able to shoot 10 fps at 1/20th second exposure, then it would surely be able to manage more than that at 1/500th, which it can't as you point out.
If it could manage more at 1/500th, Canon wouldn't sell it as a 10 fps camera, they'd sell it as a "more than 10 fps" camera, and using whichever value of fps that it could crank out at its max speed.