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Author Topic: D700 IQ  (Read 57484 times)

ErikKaffehr

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« Reply #20 on: August 15, 2008, 02:49:57 pm »

Hi,

I guess that FX and DX makes different demands on lenses. Some lenses may shine on FX an others on DX. DX has higher pixel density but uses a smaller area of the image. The relatively low pixel density on the D3 may hide some weakness in the lenses. Also the 3D probably has a quite strong AA (Anti Aliasing) filter compared to the D300. I guess that the D3 is somewhat better than the D300 with most lenses but the difference may be very small.

High ISO performance is probably better on the D3 than on the D300. The high res version of the D3 will be sharper than the present D3, unless a coke bottle is used instead of a lens.

The final question is how much sharpness is needed? Twelve megapixels are probably good enough for A3 and even A2 prints, if you print smaller I don't really think you can see any difference.

There has been a saying, "There is no substitute for square inches", and it still applies even if it may not hold under all circumstances.

In real life there are a lot of factors:

- Depth of field, improves for small apertures
- Diffraction, gets worse at small apertures
- Noise
- The ever discussed AA-filter

The postprocessing also plays a very important roll.

Erik

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Hello All,
Ken Rockwell today declared the sharpness of the D300, the D700 and the D3 to be equal and he has always raved about the color rendition of all Nikons. Would anyone be willing to reflect for a moment, for the benefit of those of us amongst the laity, what factors besides sharpness (and excluding lenses and post processing), are to be considered in choosing between DX and FX regarding IQ? If DX and FX are equally sharp is there a gain to be had in IQ by spending for the FX? Thank you.
Peter Van Dyken
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Erik Kaffehr
 

Cartman

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« Reply #21 on: August 15, 2008, 02:53:00 pm »

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Why would we assume that a larger device will produce an equal number of electrons of noise? It seems reasonable to expect instead that a increased photosite bulk produces an increase in noise sources. Also, larger well capacities require larger capacities for charge, voltage, or current all along the analog signal transport and processing chain, which seems to have the potential to increase the number of electrons of noise from sources like amplifiers (amp. noise is apparently the dominant noise source in the high end Canon's at low ISO).

This expectation is supported by data for Kodak CCDs, where total dark noise levels in electrons tend to increase with photosite size.

By the way, 1000 electrons is an absurdly high number, suggesting that you are not even vaguely aware of the real values, which run roughly from 3 to 30 electrons in spec. sheets and published measurements for SLR sensors.
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It seems that one's time on a forum and post count are directly related to their propensity to be an arse.  At best, you have poor reading comprehension and missed the part where I explain the number is an exaggerated number, which I used to make the ratios significant to be noticed.  At worst you're an A-hole who likes to mischaracterize what others have said and cast unwarranted aspersions against them.  Alternatively, you could just be an idiot.

If you had at least said something like the noise in the signal to noise ratio is the square root of the number of electrons in the well and not insulted me, I could have simply noted you as someone who is trying to be a little more precise for the OP.  

On the other hand, I don't think the OP was interested, nor at a level, to be worrying about the math.  

And it appears that you're not aware that there is really no trend for read noise dependent on pixel pitch with modern sensors.  For example, a Canon S70 has pixel spacing of 2.3 microns, a full well of 8,200 electrons, and a read noise of 3.2 electrons.  A Canon 350D has corresponding numbers of 6.4 microns, 43,000 electrons, and 3.7 electrons respectively.  While a Canon 5D has corresponding numbers of 8.2 microns, 80,000 electrons, and 3.7 electrons.

Moreover, I'm not impressed that you've seen some specs on Kodak sensors (are you an astrophotographer?).  Why don't you explain to the OP what you mean by dark noise?  And while you're at it why don't you tell him about shot noise, reset noise, output amplifier noise, white noise, and flicker noise?  Or the noise generated by various ADC's?

You could do all that yet you would illuminate no more for the OP than I did and we would still be right where I left it -- that larger pixels have a higher signal to noise ratio than smaller pixels.  

You sound like someone with just enough knowledge to make them dangerous and who thinks the laws of physics are going to be turned on their head and Nikon/Sony, Canon, Kodak, or whomever are going to release a 24 megapixel camera with the same noise levels and high ISO performance of  the D3/D700 despite smaller pixels.  

If you know how to make that work for them, I'm sure Nikon or Canon will not only pay you a fortune, but you may even win a Nobel.

If you want to know in greater detail why you're wrong in thinking that noise becomes an increasing problem as photosites get larger, this scientist has laid it out pretty well:

[a href=\"http://www.clarkvision.com/imagedetail/digital.sensor.performance.summary/index.html]http://www.clarkvision.com/imagedetail/dig...mary/index.html[/url]

http://www.clarkvision.com/imagedetail/doe...el.size.matter/

http://www.clarkvision.com/imagedetail/doe...l.size.matter2/

Thanks for reminding me why so many decent people get turned off by internet forums.  Maybe I'll spend the weekend telling people here who know what they're talking about they don't know what they're talking about so I can be as full of myself as you are.
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Panopeeper

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« Reply #22 on: August 15, 2008, 02:54:27 pm »

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Alas, I stepped in something visiting the circus and now I've besmirched the landscape
It's still luminous enough :-)

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Frames per second and high ISO shooting are not necessarily of concern
High ISO capacity is very important in landscape shooting. Not, that you select high ISO, but because the high ISO capacity is the indicator of great dynamic range.

I often run into the DR limit while shooting landscapes. My ideal camera would be a 1.3x cropping, with relative large pixels, just like the Canon 1DMkIII, but it should weight and cost much less; I don't give a fig for the frame rate.

Btw, DR measurement: DPReview's reviews are generally useful, but their DR measurement is *totally worthless*, it is like a random number generator. For example my Canon 40D allegedly beats the D3 by half stop. In reality the D3 beats the 40D by more than one stop (actually, it is closer to two stops); and this belongs to their smaller blunders, some other measurements are plainly ridiculous.
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Gabor

Panopeeper

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« Reply #23 on: August 15, 2008, 02:57:35 pm »

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There seems to be a confusion here between total image noise and individual pixel noise
The "total image noise" is a fiction. If you don't need the high pixel count, then buy a camera with less pixels but higher quality (like the D3). If you need many pixels, then don't compare your camera to one with low pixel count.
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Gabor

Tony Beach

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« Reply #24 on: August 15, 2008, 03:07:43 pm »

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Awhile back when reasearching a camera purchase I stumbled upon DPR, and I am afraid I have developed somewhat of an addiction to it. Want to kick it really do. So many incredibly impolite people.[a href=\"index.php?act=findpost&pid=215266\"][{POST_SNAPBACK}][/a]

Simple solution, tell those idiots what you really think of them.  Better still, start a few threads with titles like "This forum is full of fools and trolls", that will get Phil and his associates to kick you out soon enough.  I've been booted from DPR, Nikonians and Photo.net -- I still don't know why I was kicked out of Nikonians, so it can be really easy sometimes.  I finally had the good sense to kick myself off of Nikon Cafe by changing my email to "Bugoff@mindyourownbusiness.com".

There are just too many silly arguments founded on misconceptions (and one of the biggest purveyors of misconceptions is KR) and your reward for objecting to commonly held misconceptions is to be flamed and drawn into endless and pointless arguments.  Even after you've demonstrated why someone is wrong, the next day they will post the same nonsense in another thread and it starts all over again.  I say let people believe whatever they want to believe, let them believe that the problem is their camera and that buying a better one will overcome their lack of mastery of the technology and that their images will be sharper.
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vandevanterSH

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« Reply #25 on: August 15, 2008, 03:48:43 pm »

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It's still luminous enough :-)
High ISO capacity is very important in landscape shooting. Not, that you select high ISO, but because the high ISO capacity is the indicator of great dynamic range.

I often run into the DR limit while shooting landscapes. My ideal camera would be a 1.3x cropping, with relative large pixels, just like the Canon 1DMkIII, but it should weight and cost much less; I don't give a fig for the frame rate.

Btw, DR measurement: DPReview's reviews are generally useful, but their DR measurement is *totally worthless*, it is like a random number generator. For example my Canon 40D allegedly beats the D3 by half stop. In reality the D3 beats the 40D by more than one stop (actually, it is closer to two stops); and this belongs to their smaller blunders, some other measurements are plainly ridiculous.
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"High ISO capacity is very important in landscape shooting. Not, that you select high ISO, but because the high ISO capacity is the indicator of great dynamic range."

I am confused..(what else is new)..My 16MP back with (fat pixels) has a lot of noise at ISO 400 but seems to have good DR with landscapes.

Steve
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Panopeeper

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« Reply #26 on: August 15, 2008, 03:51:58 pm »

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My 16MP back with (fat pixels) has a lot of noise at ISO 400 but seems to have good DR with landscapes
Most probably "your back" does not offer any true ISO selection (which is a good thing). Which back is that?
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Gabor

vandevanterSH

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« Reply #27 on: August 15, 2008, 04:05:17 pm »

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Most probably "your back" does not offer any true ISO selection (which is a good thing). Which back is that?
[a href=\"index.php?act=findpost&pid=215307\"][{POST_SNAPBACK}][/a]

Hasselblad CFV I.  4080 x 4080...Has ISO 50, 100, 200, 400.

Steve
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Panopeeper

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« Reply #28 on: August 15, 2008, 04:19:19 pm »

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Hasselblad CFV I.  4080 x 4080...Has ISO 50, 100, 200, 400.
I am not sure of this one, but I guess it is not different from most others.

Most MFDB shooters don't really know the digital characteristics of their back. If you are not lazy to make a test, you can learn yours: shoot anything with constant illumination from tripod, metered for ISO 50, then 100, 200 and 400. Pls upload the raw files (yousendit.com), and we will find out the truth.

Phase One's Plus models do have different ISO gains, the other models not, nor do Sinars. Selecting a higher ISO with those cameras means simply underexposing the shot and "pushing" it in raw conversion.

(I would like to have such a DSLR.)

Addendum

See http://forum.getdpi.com/forum/showthread.p...32563#post32563 for a demonstration of what is happening.

(The Phase One P25 Plus does not have different ISO gains.)
« Last Edit: August 15, 2008, 04:31:42 pm by Panopeeper »
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Gabor

vandevanterSH

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« Reply #29 on: August 15, 2008, 04:53:55 pm »

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I am not sure of this one, but I guess it is not different from most others.

Most MFDB shooters don't really know the digital characteristics of their back. If you are not lazy to make a test, you can learn yours: shoot anything with constant illumination from tripod, metered for ISO 50, then 100, 200 and 400. Pls upload the raw files (yousendit.com), and we will find out the truth.

Phase One's Plus models do have different ISO gains, the other models not, nor do Sinars. Selecting a higher ISO with those cameras means simply underexposing the shot and "pushing" it in raw conversion.

(I would like to have such a DSLR.)

Addendum

See http://forum.getdpi.com/forum/showthread.p...32563#post32563 for a demonstration of what is happening.

(The Phase One P25 Plus does not have different ISO gains.)
[a href=\"index.php?act=findpost&pid=215312\"][{POST_SNAPBACK}][/a]

Thanks for the links...I will have to find the time to go through it.  It was/is my understanding that with, for example, my D300, the "true" ISOs 200 to 3200 are "real" because the gain is due to electronic amplification and the "L" and "H" "ISOs" below and above 200 and 3200 are not real because they are the result of software exposure correction.  So, for example a P-20 would have a fixed ISO and software exposure changes and a P-20+ would have hardware amplification for the ISO change?

Steve
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bluekorn

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« Reply #30 on: August 15, 2008, 05:31:12 pm »

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The "total image noise" is a fiction. If you don't need the high pixel count, then buy a camera with less pixels but higher quality (like the D3). If you need many pixels, then don't compare your camera to one with low pixel count.
[a href=\"index.php?act=findpost&pid=215300\"][{POST_SNAPBACK}][/a]

Is your tongue in your cheek? What is "the need" for higher pixel count? Are you referring here to people who buy into the marketing ploy that sells the camera with the highest pixel count as the "best" camera? Or are there situations that truly need a higher pixel count?

In my original question about FX vs DX I didn't mean to focus on pixel count. I was trying to understand if the total configuration of the camera with a larger sensor (and the optimum lens and most skilled post processing), the D3, would ultimately give better results in landscape photography than a camera with a smaller sensor (and the optimum lens and most skilled post processing), the D300.

I want to assume the best for myself, that someday in the not too distant future I'll begin to increase my tech skills in this world of digital photography. And if that should happen, I don't want to be looking back saying Gee, I wish I had known to buy such and such. It sticks in my mind that I've heard it said that for landscape photography the 5D is far and away better than the D3 and by asking questions about what makes for the best potential IQ I thought I could discover for myself what camera to buy.
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Panopeeper

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« Reply #31 on: August 15, 2008, 05:37:25 pm »

Quote from: vandevanterSH,Aug 15 2008, 12:53 PM
It was/is my understanding that with, for example, my D300, the "true" ISOs 200 to 3200 are "real" because the gain is due to electronic amplification and the "L" and "H" "ISOs" below and above 200 and 3200 are not real because they are the result of software exposure correction
Already 3200 is a numerical derivative of 1600 (the pixel values get doubled).

[/quote]So, for example a P-20 would have a fixed ISO and software exposure changes and a P-20+ would have hardware amplification for the ISO change?[/quote]
Is there a P20 Plus?

I know for sure, that the P45 Plus does have different gains, and I guess (based on nothing) that the P30 Plus has too. The P25 Plus is single ISO.

The difference between the fake ISOs of the DSLRs and the MFDBs is, that the DSLRs create raw images, which look like those with true ISO gains, at least at the first sight.

Take a look at the overall histograms, ISO 200, 1600 and 3200. They don't show anything special. However, the "zoomed" histograms are revealing (the next three captures). Here each pixel value is represented by one bar (a column in the histogram) (only 512 values can be shown at once). ISO 200 shows gaps in the red and blue; the meaning is, that the effective number of levels is less than 16384, and the values are "stretched" (without any good reason). ISO 1600 exhitibs the same schema. However, look at ISO 3200; if you load the images in PS and magnify them, you can easily count the effective pixel levels.

The MFDBs I have analyzed do not play this unnecessary (and for the DR counterproductive) game; the true, low (while underexposed) pixel values are stored with higher ISO and the raw converter is instructed by metadata to scale those values differently.

Anyway, the consequence is (if your MFDB is doing the same), that you should regard higher ISO as plain underexposure. If the back delivers good result even when vastly underexposed, that's great (some MFDBs are astonishingly good at it); however, there is no truly equal substitute for proper exposure.

The DR of these MFDBs is great at base ISO, because they "put everything into it", unlike the DSLRs, which show the total DR only in several shots with different ISOs. However, increasing the ISO by one stop decreases the DR of those MFDBs by one stop, while good DSLRs lose one stop in the highlight but can "gain back" perhaps 1/3 stop in the shadows.
« Last Edit: August 15, 2008, 05:39:36 pm by Panopeeper »
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Gabor

Panopeeper

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« Reply #32 on: August 15, 2008, 05:52:58 pm »

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Is your tongue in your cheek? What is "the need" for higher pixel count?
First of all, Ray compared 6 Mpix with 11 Mpix. I don't think you would qualify 11 Mpix as unnecessarily high.

Second, I don't pretent to know the market better than the camera makers. If Hasselblad at al come out with 40, 50, 60 or how many Mpix machines, then I assume that there is a market for that.

Plus, I assume that those buying these high-end cameras with so many pixels are not doing this in order to be able to downres the image to the half.

Quote
In my original question about FX vs DX I didn't mean to focus on pixel count. I was trying to understand if the total configuration of the camera with a larger sensor (and the optimum lens and most skilled post processing), the D3, would ultimately give better results in landscape photography than a camera with a smaller sensor (and the optimum lens and most skilled post processing), the D300
I would not hesitate buying the D3 over the D300 (and over the high-pixel count successor of the D3), if I could justify the cost (my special concern for edge sharpness for stitching is certainly not a general consideration).

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It sticks in my mind that I've heard it said that for landscape photography the 5D is far and away better than the D3
I would say this is BS.

I saw only one issue re image quality with the D3: banding. However, this does not affect landscaping; it occurs only when very strongly underexposed and at the same time some areas are oversaturated. Not all copies exhibit this to the same degree, and it disturbs only a few people, who are shooting for example concert in extreme low light, with lamps in the view causing oversaturation.
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Gabor

Plekto

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« Reply #33 on: August 15, 2008, 06:07:13 pm »

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Not so long ago Ken was going on about how 'full-frame' was inherently better than 'crop-frame' in terms of IQ. I guess his opinions change according to his mood.

No, technology changes.  But an idiot is still and idiot.

He is fun to read, though.  I check his site every day to see if he's written some more idiocy worth laughing at.
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BJL

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« Reply #34 on: August 15, 2008, 06:41:53 pm »

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And it appears that you're not aware that there is really no trend for read noise dependent on pixel pitch with modern sensors.

If you want to know in greater detail why you're wrong in thinking that noise becomes an increasing problem as photosites get larger, this scientist has laid it out pretty well:

http://www.clarkvision.com/imagedetail/dig...mary/index.html
[a href=\"index.php?act=findpost&pid=215297\"][{POST_SNAPBACK}][/a]

Looking at the first of your sources, figure 8a shows the 1DMkII with its big CMOS pixels to have 30 electrons of observed dark noise at ISO 100, 16 at ISO 200, etc., while figure 8b shows the S70 with its small CCD pixels to have 3 or 4 electrons of total noise. The 3 or 4 electrons of nosie that Clark mentions is an upper estimate of noise form the photosite itself, but clearly there are substantial additional sources of noise in the final signal. It seems that with Canon's DSLR sensors, the great majority of the noise is not from the photosite itself but from later in the analog stage. The main source seems to be the main ISO gain amplifier, according to an analysis I have seen. Whatever the source, undeniably the total noise is electrons is far greater for the larger photosites in this comparison. (And I do not buy the story that most of the noise comes from Canon using inadequate ADCs in its high end DSLR's.)

By the way, Clark's figures for electrons of noise are inaccurate as a measure of noise arising in the output of the ISO gain amplifier  because his correction for the ISO gain factor does not apply to noise arising after the gain. ADU's are a better bottom line measure, and dark noise in ADU's increases with ISO for the 1DMkII (and for any sensor, I would expect.)

This total observed noise has to be taken into account when considering overall S/N ratio. Of course larger photosites will still in general have better S/N ratio than smaller ones (I never suggested otherwise), but the gain with increasing pixel size is not as great as one would conclude by assuming equal total dark noise level.

By the way, the Kodak sensors I was referring to are the CCD's used in various medium format backs, the Leica M8 and R digital back, and early Four Thirds models, not astrophotography sensors.  I use Kodak for information about CCDs because Kodak publishes far more details about its CCD's than most other suppliers of CCD's for digital cameras (Sony tells us little about its DSLR sensors). Again, the main dark noise source in these CCDs might be the amplifier between photosite and ADC. For example Kodak has talked of reducing noise in its forthcoming MF sensors by reducing the amp. noise by lowering operating frequency, in turn done by having more output channels and more amps working in parallel.

Likewise Panasonic has talked of reducing noise in recent versions of its MOS sensors by reducing amplifier noise. So amp. noise seem repeatedly to be indicated as a major sensor noise source, at least when the S/N ratio of the photosites is high enough to put high demands on amp. performance.
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BJL

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« Reply #35 on: August 15, 2008, 06:55:50 pm »

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The "total image noise" is a fiction. If you don't need the high pixel count, then buy a camera with less pixels but higher quality (like the D3). If you need many pixels, then don't compare your camera to one with low pixel count.
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Maybe some people want high resolution at low ISO speeds (for highly detailed stationary subjects like landscapes), while accepting less high resolution at higher ISO (for moving subjects). [We used to use different films for that!]

If a high pixel count sensor has good enough noise levels at lower ISO speeds, it becomes interesting to ask how its "image noise level" at high ISO compares to that of a lower pixel count alternative: suitably processed prints of the same size is my preferred comparison.

Anytime that higher and lower res. sensor alternatives are about equal in "total image noise" or "visible noise on same-sized prints", the one that also offers higher resolution without visible noise problems at lower ISO speeds has an overall IQ advantage. The idea in some digicams of having higher ISO settings only available at lower pixel counts is maybe not so stupid.
« Last Edit: August 15, 2008, 06:58:08 pm by BJL »
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vandevanterSH

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« Reply #36 on: August 15, 2008, 07:06:50 pm »

[]
[/quote]

"The MFDBs I have analyzed do not play this unnecessary (and for the DR counterproductive) game; the true, low (while underexposed) pixel values are stored with higher ISO and the raw converter is instructed by metadata to scale those values differently."



Can the Back manufacture call a "ISO" ISO if the effect is accomplished using software vs hardware amplification.  That is the explanation that I was given for Nikon using the "L" and "H" notation.  

For a hypothetical, if I assume that my CFV back has a fixed "hardware" ISO of 50 and the preview and histogram are based on an  instruction for the "future" RAW conversion, should I push the histogram to the right using  a fraction of or a full stop for several shots?   I'll look as some shots that were pushed way to the right and see if the highlights are really blown.  Or am I going out into the "weeds" here?

Steve

Steve
« Last Edit: August 15, 2008, 07:07:47 pm by vandevanterSH »
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Panopeeper

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« Reply #37 on: August 15, 2008, 07:47:09 pm »

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Anytime that higher and lower res. sensor alternatives are about equal in "total image noise" or "visible noise on same-sized prints", the one that also offers higher resolution without visible noise problems at lower ISO speeds has an overall IQ advantage. The idea in some digicams of having higher ISO settings only available at lower pixel counts is maybe not so stupid.
The wish is understandable. However, this situation exists only in fairy tales; two half-pixels don't make one whole, and one whole pixel does not make two halves.
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Gabor

Panopeeper

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« Reply #38 on: August 15, 2008, 08:00:03 pm »

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Can the Back manufacture call a "ISO" ISO if the effect is accomplished using software vs hardware amplification
They are not in the habit of asking for permission before ignoring and violating standards. At the present, they can do anything and much of the crowd will be cheering.

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For a hypothetical, if I assume that my CFV back has a fixed "hardware" ISO of 50 and the preview and histogram are based on an  instruction for the "future" RAW conversion, should I push the histogram to the right using  a fraction of or a full stop for several shots?
Speculations are a recipe for disaster. It is the question of simple fact, which can easily be determined.

The essence is, again: *if* the ISO gain is real, you can count on some fraction gain by increasing the ISO. The light is not enough, you increase the ISO; you lose one stop in the highlights, and this loss may be "empty" if there are none, but anyway you gain something in the shadows.

However, with the fake ISOs you don't gain anything in the shadows. If you lose something in the highlights depends on the implementation: with DSLRs you alway lose one stop with every ISO stop, because clipping on the level of raw data occurs even if no pixel saturation occured. With the "ISO-less" MFDBs the loss is nominal: the raw data is there, but the raw converter may discard it; this depends on how the camera passes this information along, and how the raw converter reacts. The only certain aspect is, that there is nothing to save with such DSLR raw files, but the MFDB raw files can be manipulated into "recovering" that, what is there but the raw converter believes it is not there.

An example would be much more useful for demonstration than talking about hypothetical situations.
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Gabor

Tony Beach

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« Reply #39 on: August 15, 2008, 11:35:08 pm »

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It sticks in my mind that I've heard it said that for landscape photography the 5D is far and away better than the D3 and by asking questions about what makes for the best potential IQ I thought I could discover for myself what camera to buy.
[a href=\"index.php?act=findpost&pid=215333\"][{POST_SNAPBACK}][/a]

I do not even think the 5D is "far and away better" than the D300; that tidbit you heard sounds exactly like the kind of trash KR peddles.  Most of what distinguishes the image quality coming from these cameras at or near base ISO is the lens you put on it.  Understanding exposure, utilizing optimum shooting discipline and using appropriate post processing will deliver exceptional photographs with all the high end DSLRs, to get appreciably more than that you should skip the smaller formats and graduate to MFDBs.  This all comes back to people wanting to make up for their lack of understanding and skills by buying a "better" camera, and that's precisely the crowd KR is preaching to.
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