Reading through a photo magazine I saw an ad for DXO mark - http://www.dxomark.com/ (http://www.dxomark.com/) -This was discussed maybe a month ago.. I think DXO have their own agenda, I have (and love) a D3 as well as an H3D31 (love it too), each have their place just as the equivalents did in the film days. I'm no scientist and frankly cannot be bothered to examine the science behind DxO's claims.
a company that claims to test raw image quality of most cameras and backs based on
color deapth, dynamic range, and low light ISO.
Looking through their database, they rate D3X the highest, and it was quite shocking to see H3DII-39 and P45+ come in well behind
many prosumer grade DSLR's...
I did not expect medium format to do well in low light ISO, but they rank behind many DSLR's even in color deapth and dynamic range...
Is there any sense in what these guys are doing? I'm curious if anyone is familiar with their test methods.
thanks!
-ilya
This was discussed maybe a month ago.. I think DXO have their own agenda, I have and love a D3 as well as an H3D31 each have their place just as the equivalents did in the film days. I'm no scientist and frankly cannot be bothered to examine the science behind DxO's claims. I do know for a fact that certain gear works better than other gear for certain jobs..
Nick-T
I agree with you, and I missed the original discussion... from personal experience, I know that D3 is a LOT better at low light and fast action photography than an H3D-39, but when it comes to image quality, D3 can not really compare. That's why it seems so shocking that DXO found D3 to produce better
image quality...
oh well - I was only curious.
Reading through a photo magazine I saw an ad for DXO mark - http://www.dxomark.com/ (http://www.dxomark.com/) -
a company that claims to test raw image quality of most cameras and backs based on
color deapth, dynamic range, and low light ISO.
Looking through their database, they rate D3X the highest, and it was quite shocking to see H3DII-39 and P45+ come in well behind
many prosumer grade DSLR's...
I did not expect medium format to do well in low light ISO, but they rank behind many DSLR's even in color deapth and dynamic range...
Is there any sense in what these guys are doing? I'm curious if anyone is familiar with their test methods.
thanks!
-ilya
They put no weight on resolution just take it into account regarding noise measurements.
It seems to be a very common mistake to disregard resolution when comparing noise samples. People tend to view both images at 100% to look at the noise, which is understandable, but they forget that each pixel of noise on a 39MP camera is only going to be one quarter the area on the final print compared to a pixel of noise from a 10 MP camera. Big difference, and this means that on a per-pixel basis, the 39MP camera can afford to be a lot more noisy. It also means that noise reduction can be applied more aggressively and you will still be left with more detail.I thought that too, but then d3x came in ahead of d3. How can that be?
I thought that too, but then d3x came in ahead of d3. How can that be?
It seems to be a very common mistake to disregard resolution when comparing noise samples. People tend to view both images at 100% to look at the noise, which is understandable, but they forget that each pixel of noise on a 39MP camera is only going to be one quarter the area on the final print compared to a pixel of noise from a 10 MP camera. Big difference, and this means that on a per-pixel basis, the 39MP camera can afford to be a lot more noisy. It also means that noise reduction can be applied more aggressively and you will still be left with more detail.
Sony sensor and a newer processor
It seems to be a very common mistake to disregard resolution when comparing noise samples. People tend to view both images at 100% to look at the noise, which is understandable, but they forget that each pixel of noise on a 39MP camera is only going to be one quarter the area on the final print compared to a pixel of noise from a 10 MP camera. Big difference, and this means that on a per-pixel basis, the 39MP camera can afford to be a lot more noisy. It also means that noise reduction can be applied more aggressively and you will still be left with more detail.DxOMark put the different resolution into the equation with the 'Print' option in the DR and SNR18% tests:
My interpretation is that the H3DII 39 has just one real ISO: ISO50. All over values are fake ISOs obtained from ISO50.
I think that's true for all MFDBsIt seems the Phase One has ISO50 and 100, and the Leaf ISO50, 100, 200, 400 and 800. Only the Hasselblad has a unique real ISO, of 50.
It seems to be a very common mistake to disregard resolution when comparing noise samples. People tend to view both images at 100% to look at the noise, which is understandable, but they forget that each pixel of noise on a 39MP camera is only going to be one quarter the area on the final print compared to a pixel of noise from a 10 MP camera. Big difference, and this means that on a per-pixel basis, the 39MP camera can afford to be a lot more noisy. It also means that noise reduction can be applied more aggressively and you will still be left with more detail.
I think that's true for all MFDBs
what is the difference between the way D3X and H3D-39 derive higher ISO's?Real ISOs refer to the gain of the amplifier that feeds the captured information from the sensor into the AD converter.
I think that's true for all MFDBsThis is not so straightforward. I can make definitive statements only relating to a few models and a few ISO steps:
Real ISOs refer to the gain of the amplifier that feeds the captured information from the sensor into the AD converter.
Fake ISOs are shots obtained at a different (usually lower) real ISO value and then overexposed by the camera software.
A camera usually has some real ISOs, and also several fake ISOs. For example on a Canon 5D, ISO3200 is fake ISO. The shot is actually taken at ISO1600 and then overexposed by 1 stop (all levels are multiplied by 2) before saving the RAW data.
A fake ISO like the ISO3200 on the Canon 5D has no noise advantage when shooting RAW over shooting at the same aperture/shutter using the lower real ISO (ISO1600 in the example), because it's actually a ISO1600 shot. But the fake ISO can make us loose up to 1 stop of highlights information because of the overexposure.
So fake ISOs should always be avoided when shooting in RAW mode or we can loose DR in the highlights when comparing to shooting at the same aperture/shutter with the highest real ISO.
In JPEG mode all ISOs are fine, as long they help us to achieve the correct exposure in the final image, since this will be hardly corrected.
Looking at the plot, it seems the Hasselblad has only one real ISO (ISO50). When setting ISO100, 200 or 400 on that camera, the shot will be internally done at ISO50 and then respectively overexposed by 1, 2 or 3 stops in software. So shotting at any ISO over 50 in the Hassy is useless and can make the user loose highlights information with respect to using the same aperture/shutter and ISO50.
BR
DxOMark put the different resolution into the equation with the 'Print' option in the DR and SNR18% tests:
Oh - very interesting - thanks!
So, does that mean that in Nikons all the"Hi" and "Low" settings are the fake software ISO's and the ones designated with actual numbers are real internal amp setting ISO's?
Now, these 39MP back are old technology, and it would be interesting to see what companies like Kodak and Dalsa could do with 39MP if they tried today, but it seems that they have been stucked in the MP race like everybody else and will not develop any new sensor with that kind of resolution.
Cheers,
Bernard
So, does that mean that in Nikons all the"Hi" and "Low" settings are the fake software ISO's and the ones designated with actual numbers are real internal amp setting ISO's?The designation is meaningful only in one direction: the ISO steps with special designation like "Hi" or "boosted" are usually fake; however, those not designated as such may be real or fake.
The designation is meaningful only in one direction: the ISO steps with special designation like "Hi" or "boosted" are usually fake; however, those not designated as such may be real or fake.
Examples
Nikon D300 and D90: ISO 6400 is designated as "boosted", but already 3200 is fake
Nikon D3: this is "correct", i.e. ISO 6400 is analogue supported.
The same is happening in the Canon line.
However, this is is much less interesting than the factual usefulness. Most of the top analogue ISO steps are purely eye-wash; there is nothing to gain over 1600, no matter if Canon or Nikon. The only exception is perhaps the Canon 1DMkIII, 3200 seems to contribute a tiny bit compared to 1600.
I think it's interesting that anywhere above 50 ISO the DSLRs beat the backs in terms of D.R. Often by one or two full stops, even though the backs have larger pixels. I am really wondering where the truth lies.
It's easy to find threads here and elsewhere where one guy claims that in terms of D.R. his back "blows away" his Canons, and then right after that someone else says that their back is no better than their Canon. Maybe it's because they are shooting at different ISOs...
Click the Dynamic Range tab here (http://www.dxomark.com/index.php/eng/Image-Quality-Database/Compare-cameras/(appareil1)/305|0/(appareil2)/301|0/(appareil3)/304|0/(onglet)/0/(brand)/Canon/(brand2)/Hasselblad/(brand3)/Phase%20One)to see what I am talking about:
http://www.dxomark.com/index.php/eng/Image...d3)/Phase%20One (http://www.dxomark.com/index.php/eng/Image-Quality-Database/Compare-cameras/(appareil1)/305|0/(appareil2)/301|0/(appareil3)/304|0/(onglet)/0/(brand)/Canon/(brand2)/Hasselblad/(brand3)/Phase%20One)
Maybe it's the fashion guys who are often shooting at higher ISOs because they are mixing daylight with strobes and such - and are therefore not seeing the DR advantage of the backs (because there is apparently no advantage at 400ISO) and the landscape/architecture guys who are seeing the backs as having better D.R. only because they are shooting at ISO 50?
I do not currently have a back in my possession or I would attempt to confirm this on my own...
I think it's interesting that anywhere above 50 ISO the DSLRs beat the backs in terms of D.R. Often by one or two full stops, even though the backs have larger pixels. I am really wondering where the truth lies.If you read carefully this thread you will find the answer: backs have only one or two real ISOs, the rest are fake ISOs obtained by overexposing in software a lower real ISO. With every extra fake ISO stop, you are losing 1 stop in the ability to capture DR.
If you read carefully this thread you will find the answer: backs have only one or two real ISOs, the rest are fake ISOs obtained by overexposing in software a lower real ISO. With every extra fake ISO stop, you are losing 1 stop in the ability to capture DR.
Are backs wrongly designed? no way, they were designed for applications where usually the base native ISO is used everytime.
BR
With every extra fake ISO stop, you are losing 1 stop in the ability to capture DR.
Regarding this REAL ISO question... Do MFDB people admit to this? I'm attending a Hasselblad event on Tuesday and will ask them about it.Sadly they will probably not understand a word about what you're talking about.
is there a way to fake ISO by smartly pushing up only shadows and slightly lighting up the midtones, without blowing out the highlights?Sure! you are talking about... postprocessing that's easily done in Photoshop, or even in the RAW developer with the Brightness control, which unlike the Exposure control allows to lift the shadows without blowing the highlights.
Sure! you are talking about... postprocessing that's easily done in Photoshop, or even in the RAW developer with the Brightness control, which unlike the Exposure control allows to lift the shadows without blowing the highlights.
BR
so I think they would understand..maybe they aren't as clever as you but I think they understand how their backs work.It's not a question of being clever, but just interested in those matters. I am glad to see the people you bought the back from were not only informed but also honest. I hope photolinia will tell us how was his event.
My question was obviously about the on-chip shadow-pushing-up before making up of the RAW file.That's RAW cooking, and nobody should be interested in that. First because is useless (it can be done better in postprocessing), and second because it would ruin the virgin and linear condition of the RAW file.
Hmmm... Could somebody explain this real ISO vs fake ISO issue?
I thought that all cameras had one base ISO (50 for most MFDB, 100 for D3X, 200 for D3), but then
used amps to simulate the effect of higher ISOs - is that not the case?
what is the difference between the way D3X and H3D-39 derive higher ISO's?
-ilya
I think it's interesting that anywhere above 50 ISO the DSLRs beat the backs in terms of D.R. Often by one or two full stops, even though the backs have larger pixels. I am really wondering where the truth liesThe cases have to be separated.
OK, I'll throw some gasoline on the fire :-)
OK, I'll throw some gasoline on the fire :-)
I shoot primarily landscapes and use a P45+ on a Mamiya 645 II, as well as a D3 (one of these days I'll upgrade to a D3X). The only thing the P45+ gives me is more pixels, and no AA filter getting in the way of those pixels. There, I said it out loud. Believe me, I take no pleasure in saying that, given how much I spent on the P45+ kit. But that's what I'm seeing.
More pixels is no small thing, and the lack of an AA filter further helps out, and in fact these are the two primary reasons I got the P45+ kit. The detail available in a MFDB file is breathtaking. But as for all the other so-called advantages attributed to MFDBs, I'm not seeing them. If anything, I agree with DxO's assessment here. Maybe these other advantages were real a few years ago, but with the latest crop of DSLRs, the gap has narrowed considerably. I have no trouble pulling clean sharp detail out of the shadows with my D3. If anything, I rank the D3 slightly superior to the P45+ in this regard (based on using the D3 at ISO 200 and the P45+ at ISO 50, their respective base ISOs). And the D3 has more mid-tone to highlight DR than the P45+, again at base ISOs. The P45+ saturates at around 2 and 2/3 to 3 stops over mid-tone. The D3 highlights don't hit the limit for another two thirds to a full stop beyond that. And the D3X is reportedly even better in this regard.
On top of all this is the convenience factor in Nikon's (and Canon's) favor. I have excellent quality super wides to super telephotos, and everything in between. I have an excellent selection of tilt/shift lenses. I have blazingly fast AF. My batteries last days, not hours. And I have superb in-camera live view that allows me to achieve critical focus to a much more repeatable and precise degree than I've ever been able to achieve with my MF kit.
One of these days I'll get a D3X, and I doubt I'll pull the P45+ kit out much after that, based on what I've seen to date.
Regards,
Mort.
Sadly they will probably not understand a word about what you're talking about.
Sure! you are talking about... postprocessing that's easily done in Photoshop, or even in the RAW developer with the Brightness control, which unlike the Exposure control allows to lift the shadows without blowing the highlights.
BR
Charming.Amazingly valuable and detailed information about your product you are providing here. You can take a rest now.
Anyway, there are differences in the DSP functions regarding higher ISO settings on the camera, but then again, I probably don't know what I am talking about.
Regardless of how A to B is reached, if the result is a useable image of expected quality, who really cares?My first reaction was this is the argument of a used car salesman. However, my experience shows, that not only many but perhaps the majority of the owners don't have much idea about the characteristics of their cameras in general. The owners of MFDBs are not excepted, or if they are, then rather on the ignorant side. No problem, it's their money. Thus the position "don't care for details as long as you are happy" is justified.
.... the imaginary 16bit depth of Phase One backs....
On a separate note..
Regardless of how A to B is reached, if the result is a useable image of expected quality, who really cares?
True, on the other hand if you do the same computation between a 39MP back and a D3x, you will realize that a the same DPI, the linear size of the print you can achieve is only 1.25 times larger, meaning that you can go from an A4 print (29.7 cm long) to one that is 37cm long.
It can of course be argued that the 39MP AAfilter less back has higher pixel quality, which is true to some extend.
Now, these 39MP back are old technology, and it would be interesting to see what companies like Kodak and Dalsa could do with 39MP if they tried today, but it seems that they have been stucked in the MP race like everybody else and will not develop any new sensor with that kind of resolution.
Cheers,
Bernard
There's like a mile of gap between my 5D and my older P20 (non plus) and that's even when I use the brilliant Leica R lenses on my canon. There's several stops of usable DR more on my p20 than the 5D. If the 5D 2 got 1 stop more DR than the 5D classic then it still wouldn't match up to my 5 year old P20. I am a big doubter that the 5D2 or D3X are going to replace even 2 or 3 generation older MFDB's for studio use. I think Michael wrote in the first DXO/MFDB thread why the DSLR numbers come out so favorable for DR - something about in camera noise reduction while MFDB's rely on on RAW processing software. The DXO numbers for at least DR are not useful for comparing DSLR to MFDB.
Actually, the linear size is only 20% bigger, unless the Nikon version of the Sony sensor is different. My a900 is 6048 pixels wide; the P45+ is 7216 wide. (Height, on the other hand, is 34% greater.)
Having said that, I have on several occasions shot the same image with both sensors, adjusting zoom lenses to ensure the images are the same size linearly, and my eyes on-screen and more importantly in print, tell me the MFDB image is clearly superior in detail and tonality.
It is interesting to note that the people who claim that MFDBs are "better" generally talk about what they see, and what their customers see, i.e. a clear visual superiority for the MFDBs. The people who claim that the difference is very small are generally talking about statistics, plots, measured noise, and so on. There are a small number of people who go against the stream and claim that they can see no difference, or measure no difference.
Talking fake and not fake ISO is pejorative. We should be talking analogue gain and digital gainThis is BS. "Digital gain" in the current context is an oxymoron.
Nick,
Other than file size and resolution, what other aspects of MF photos do your clients prefer? I think the clients do not always know best
and often know very little, but of course they pay, so they get to choose...
-ilya
These people are fascinated by the inner workings of digital imaging and good luck to them. None of these people as far as I can see make a living taking photos...The greatness of the MFDBs is in my eyes, that they outperform the DSLRs even if their users don't know how to use it optimally.
I make a living from taking photos and my digital backs out perform my DSLRs and my clients can tell the story.
It is interesting to note that the people who claim that MFDBs are "better" generally talk about what they see, and what their customers see, i.e. a clear visual superiority for the MFDBs. The people who claim that the difference is very small are generally talking about statistics, plots, measured noise, and so on. There are a small number of people who go against the stream and claim that they can see no difference, or measure no difference.
This leads me to wonder about two things:
1) Could they both be true? In other words, could it be that the MFDBs give visually noticeably more appealing results, while there is little measurable difference? That would mean that what we measure doesn't translate directly to what we feel about the results. This would lead me to think that if we want to measure how good something is, we need to come up with new tests and new ways of measuring. Especially the DR results make me think this. One hears repeatedly how much cleaner the shadows are with MFDBs, but this somehow doesn't translate into better DR results, counter-intuitively, I suppose because what we like and what we can measure don't match.
2) Could it be that the 35mm-FF camera manufacturers know about the lack of significant measurable differences, and are actively pushing this angle by "cooking" the results to obtain the best possible *measured* result? They must surely know that very few people will ever see top-notch MFDB results, and that cooking the results to minimize the measurable differences helps them sell more cameras. This is somewhat analogous to graphics card manufacturers writing drivers which are specifically optimised for certain gaming performance benchmarks, while performing no better than other cards in actual play...
I am curious about this comment (genuinely curious, not looking to poke holes in it). I presume you are comparing the P45+ and the A900, not some other cameras. Could you explain in a bit more detail what the differences are that you see, and that you feel while working? Do you use the same software for both?
I would love a P45+, but my budget today barely stretches to an A900, which is why I am interested.
Could you elaborate on this please?The Phase Ones create nominally 16bit raw data. In fact, the pixel values are 16bit wide, i.e. they go up to 65535. However, about two bits of that are not only useless, they are actually detrimental; if the raw processing requires so much pushing, that the low-order two bits become apparent in the result, then the photographer becomes unhappy with the camera (back).
I shoot about 50% in a studio and 50% on location. I think in a studio MFDB wins by a mile, but on location it can be tricky.If you really really really need to print big, and your revenues will benefit from printing big, then MFDBs make a lot of sense. However, it's all too easy to be seduced by those gorgeously detailed files, and to convince yourself you need MFDB when you really don't. Only you can answer that question. If I were you, I'd rent a D3X (or a 1DsIII) and shoot the same subjects that you shot with the MF system, and then print them side by side at the same print sizes you're currently selling to customers. Unless you are printing really big, I doubt you're going to see a huge difference, if any. And after all, it's prints you sell, not the files.
Basically, I'm at a cross road between a D3X and a used MFDB, and it sounds like given the choice you would go for a D3X...
Usable DR is a lot less than what you come up if you measure just the DR as technically defined and there are big differences in how these numbers shift by cameraIt depends on the definition of dynamic range adopted for the measurement. The engineering (scientific) definitions is IMO total waste of time and bandwidth relating to photography, so is DxO's 18% etc. measurement.
This is BS. "Digital gain" in the current context is an oxymoron.
The Phase Ones create nominally 16bit raw data. In fact, the pixel values are 16bit wide, i.e. they go up to 65535. However, about two bits of that are not only useless, they are actually detrimental; if the raw processing requires so much pushing, that the low-order two bits become apparent in the result, then the photographer becomes unhappy with the camera (back).
I do STRESS however, that at smaller sizes like A3, you'd be very hard pressed to tell the difference. I only see teal value in MFDB if you're going to print big. For all other work, especially wildlife, DSLRs are way superior.That's the key. I totally agree with being hard pressed to see a difference at A3. That's true even with my D3 files compared to my P45+ files. At A2 I can more readily see a difference, but both prints still look fantastic. Someone thinking about getting a MFDB system should ask themselves if this difference is enough to justify the extra cost and inconvenience of going MFDB. For some people, the answer will be yes, for others it'll be no. If printing bigger than A2 helps the bottom line, the answer becomes more and more obvious in favor of MFDB the bigger you print.
If you really really really need to print big, and your revenues will benefit from printing big, then MFDBs make a lot of sense. However, it's all too easy to be seduced by those gorgeously detailed files, and to convince yourself you need MFDB when you really don't. Only you can answer that question. If I were you, I'd rent a D3X (or a 1DsIII) and shoot the same subjects that you shot with the MF system, and then print them side by side at the same print sizes you're currently selling to customers. Unless you are printing really big, I doubt you're going to see a huge difference, if any. And after all, it's prints you sell, not the files.
I haven't bought a D3X yet because, like you, I'm put off by Nikon's pricing strategy. A D3X costs way less than I paid for my P45+ system, of course, but I don't want to reward Nikon for what I consider to be a horrible marketing decision. Plus I already have the P45+ system for my high MP needs, so I'm reluctant to purchase something else that satisfies the same purpose. Nevertheless, knowing what I know now about how D3 files compare against P45+ files, and the inconvenience of using two systems, and the inferiority of MF autofocus, metering, lenses, live view, etc, I think a D3X would be a better match for my needs than the P45+ system. If a D700X with the D3X sensor in it ever appears, it'll be a no brainer, and that's basically what I'm waiting for (although it's getting harder and harder to resist the D3X :-)
We all have our tricks on handling the files and experience doing real work is very valuable - much more so than pushing the files around in a program that measures noiseThis is not the same issue as the dispute over the use or uselessness of 14bit vs 12bit; the 16bit issue of the Phase Ones is not the question of noise. The two low order bits are not usable (not not useful) in the image reproduction.
So you don't like the term - then suggest a more appropriate one and be positive about it rather than heckle and call BSThis is not the question of liking or not. Analogue ISO gain "reveals" image information captured by the sensor but not utilized at lower ISOs; that's the point of having them.
The "fake ISO" of DSLRs is done wrong though - they just apply a gain in post A-to-D digital signal before recording it, which brightens the image and throws away a stop. If they'd left it alone and just metadata tagged +1EV or whatever, all would still be in the RAW and all would be good.There is no justification for what the DSLR manufacturers are doing.
This is not the same issue as the dispute over the use or uselessness of 14bit vs 12bit; the 16bit issue of the Phase Ones is not the question of noise. The two low order bits are not usable (not not useful) in the image reproduction.
Come on - the two lowest bits represent 0, 1, and 2 values out of a total of 65536and 3 :-( (i.e. four values out of 65536). On the other hand, this is not an issue of bits, that is only a convenient way of expressing such aspects.
Who gives a cr*p about that?Let's keep things straight.
Most people adjust the black point higher anyhow even if they push up the shadowsYou can't adjust the black level in terms of raw pixel values. Nevertheless, you are right in that those pixels are not used in most cases. I wrote before: The two low order bits are not usable (not not useful) in the image reproduction.
The problem is chromatic noise and blob type of noise and banding up in the 1/4 tones of the image, not those two last bitsSome of the banding (or all of it) is caused by those bits (i.e. by the far too great depth of the data, which represents tiny sensor related issues, not image information).
I am not certain you can take DXO's numbers across from DSLR to MFDB like apples to applesActually, I don't take DxO's nor anyone else's numbers at all. I prefer my own measurements, which I can document and demonstrate. If I don't have raw files suitable for such measurements, then I don't make any related statement.
As far as DR - thanks for clarifying how DXO is defining DRHold on; I described, how I do the measurements (the graphs I linked to are mine). I don't know how exactly to interpret DxO's measurements.
As to Fake ISO - actually I understand why a camera company would do this - its just easier to operate the camera this way with exposure metering and exposure checking on the histogram. If I were making a camera I'd probably do the same thingDon't be so sure you would do the same.
Especially the DR results make me think this. One hears repeatedly how much cleaner the shadows are with MFDBs, but this somehow doesn't translate into better DR results, counter-intuitively, I suppose because what we like and what we can measure don't match.Are you sure those who say how much cleaner the shadows are with MFDBs (funily without specifying which MFDB nor which DSLR) really know how to evaluate noise in the shadows of their MFDBs? even if they are MFDBs selling staff who think they know what they are talking about, or they are people making a living on using these backs and thinking making a living on using their backs is the only way to have a founded opinion.
The black figure is located in the RAW range 9 stops from saturation. I am pretty sure the level of noise in the 9th stop on a Nikon D3X is the same or lower than this.
It is an interesting image, but you left out a lot of information. At what ISO is this? Which H3DII is it? Do you have a similar crop from a D3X to demonstrate your assertion?
Filename: hassel.dng
Timestamp: Thu Nov 13 16:54:51 2008
Camera: Hasselblad H3D II-31
DNG Version: 1.0.0.0
ISO speed: 100
Anyway ISO is irrelevant here, since all ISOs in this back are ISO50.
I have never seen any RAW file from Nikon D3X but I did for a Nikon D3 having similar noise in the 9th stop (signed as -8EV here):
(http://img504.imageshack.us/img504/7571/zonas2oq6.jpg)
I think the quality advantage for backs is not noise, DR, colour rendition,... but just sharpness and resolution, i.e. detail. In the same way as a Leica M8 with an average sensor can produce very good quality images thanks to the lack of AA filter and superb optics, backs have the same strongholds: no AA filter and good lenses. The sensor in backs is not better than in DSLRs.
BR
Converting to DNG will see a significant rise in noise levels compared to retaining our 3F format and using Phocus.Brilliant.
Anyway ISO is irrelevant here, since all ISOs in this back are ISO50.
Well, no. If you shoot at "fake" ISO 100 or 200 or 400, you are under-exposing, in effect, and thereby reducing the quality of the image.I know, but according to the ISO plots from DxO Mark and what Gabor commented (fake ISOs in this back are not software corrected, i.e. they are just metadata), the RAW data captured is the same at ISO50 as at ISO100, so the area analysed was actually 9 stops below sensor saturation, no matter what ISO was set in the camera.
Brilliant.
If anything, you would want to test on a genuine Raw file wouldn't you, instead of something that is a conversion from the real thing? (where just about everyone that is using/involved with Hasselblad knows by now that DNG conversion results in loss of quality.)Yes and no. If a genuine file from the back produces a better result when processed with the camera software, is because software corrections are being applied, not because there was a loss of quality when converting to DNG (or you think that for some strange reason noise will increase in the conversion?).
If you shoot at "fake" ISO 100 or 200 or 400, you are under-exposing, in effect, and thereby reducing the quality of the image. This is not irrelevant at allIf the analogue gain is identical for different ISOs, then the ISO selection is only for metering, thus the shot gets underexposed with higher ISO.
Yes and no. If a genuine file from the back produces a better result when processed with the camera software, is because software corrections are being applied, not because there was a loss of quality when converting to DNG (or you think that for some strange reason noise will increase in the conversion?).This is not a straightforward issue.
In addition to this the comparision to any other camera would not be fair since not the same RAW developer would have been used for both. That is why I always use DCRAW and ignore any metadata found in the RAW file
On the other hand, I do not accept blindly that the Hasselblad raw files could not be converted in DNG; perhaps they are not converted properly, because Hasselblad and/or Phocus don't give a damn for their customers' workflow. For example the Sinar files (multiple files for one raw image) are converted in DNG by two non-Adobe converters, differently but resulting largely in the same final output except for colors (which is the issue of the converter, not of DNG).
Keep in eyes, that Phocus does not make business by creating input files for Adobe.
For example the Sony noise reduction on the raw data greatly reduces the resolution; that is not acceptable without the user wanting that.
If there is an impression that we fudge the DNG conversion to make us look favorable, then I am afraid in our evil underground lair, we are not that clever.David, you posted earlier
Converting to DNG will see a significant rise in noise levels compared to retaining our 3F format and using Phocus. Therefore showing such an image is an unfair evaluation.
I presume you are talking about the A900? The NR can be turned off, can it not?Not for low ISOs, but most owners beleive it can. See a very technical study (http://www.cryptobola.com/PhotoBola/SonyA900/SonyA900_NR.htm) of this topic (although I thought you had seen this on GetDPI).
Ive extensively used two Canon 21mp bodies, and now shoot with a Phamiya P45 refurb with assorted Mamiya glass. With Canon i used Camera Raw or Lightroom, with Phase I use C1 4.7.
There is no comparison in image quality. The Phase files are on a whole other level of clarity. And not just in terms of 21MP vs 39MP relative size.
A Phase-derived image looks like my old 4x5 prints in describing detail. The Canon prints should not be printed past 200% base resolution.
I could have been misusing the Canon gear, or have gotten two bad cameras, or should not have processed the files in Lightroom, but in my working experience some people are better served by the Canon and Nikon gear, and some are better served by MFDBs.
However, neither is unequivocally better.
There are some very good reasons to stick with Canon
1- Not everyone prints large enough so the Canon dough-ball looking pixels become apparent. When the prints are small, an invisible pixel is an invisible pixel. If I didn't require a certain amount of detail in my work, I would have happily kept my Canon. And several thousand dollars.
2- Much of the deficiency with Canon gear may be in the lenses, which when sharp, don't seem that sharp. However, the whole problem is probably the AA filter. As far as I can tell. The description detail in a Canon image is rather fugly. However, I have only had my work to judge this on... I would love to see a scientific comparison of Canon primes vs Mamiya vs Rodenstock/Schneider digitals in Helical mounts all compared on one sensor.
3- If I shot action, needed lowlight, or needed any real photographic versatility, I would happily have kept my the Canon. And several thousand dollars.
When I asked for a refund, as the software is useless to me, and nowhere in the documentation is it specified that it only works with smaller files, they simply refused.
May I suggest simply using your eyes people? !??!!
What? Are you mad! Photography isn't about what you SEE!!! It's about numbers! Sheesh.
Nick-T
May I suggest simply using your eyes people? !??!! Make up your own mind by looking at whatever medium you generally use or distribute. Sheesh
May I suggest simply using your eyes people? !??!! Make up your own mind by looking at whatever medium you generally use or distribute. SheeshMay I ask what exactly "people" should use their eyes for? Honestly, do you have the slightest idea what the discussion is about?
May I ask what exactly "people" should use their eyes for? Honestly, do you have the slightest idea what the discussion is about?is about:
is about:
Stop! otherwise you go blind!
Aw c'mon - it's about GEAR! Sheesh....No no, the game of "forum fantasy fotography" it is not just about numbers or just about gear: it is about proving the superiority of your gear with a single number, and arguing which single numerical measure should be used: MP, ISO, DR, DxOMark ...
No no, the game of "forum fantasy fotography" it is not just about numbers or just about gear: it is about proving the superiority of your gear with a single number, and arguing which single numerical measure should be used: MP, ISO, DR, DxOMark ...
I mean who gives a care what DXO says?Among others, you. Otherwise you'll have to explain why you decided to invest your time in reading and posting on a thread entitled as 'DXOmark ranks DB image quality well below DSLR!'.
DXOmark results are a nonsense when you have in your computer thousands of photo with Canon 1Ds Mark III and P45 ...
I think it's interesting that anywhere above 50 ISO the DSLRs beat the backs in terms of D.R. Often by one or two full stops, even though the backs have larger pixels. I am really wondering where the truth lies.
ISO is probably an ancient term which should not be used with digital, but it is what we know and is what is familiar to us photographers.I would agree with this if you had said ASA; ISO is just an upstart.
It's because if you use "fake" ISO settings, which most MFDB do for their higher settings, every stop above the highest "real" ISO comes directly out of DRNot so. This is the way DSLRs adopt ISO steps without hardware support; this is an inexcusable dumb rubbish from the DSLR manufacturers.
Not so. This is the way DSLRs adopt ISO steps without hardware support; this is an inexcusable dumb rubbish from the DSLR manufacturers.
MFDBs, at least those I have analyzed, work differently: they do not ruin the original pixel values by senseless multiplication (or division); they simply state, that the numerical range of the pixel values is now lower than with another ISO, but this occurs without causing clipping of the pixel values.
Thus the DR of the MFDBs does not change with the fake ISO increase, in contrast to DSLRs.
What's the reason for the decrease in DR as the ISO increases as can be seen over at DXOmark? IT looks like as soon as you hit ISO 100 or above the DSLRs win in terms of D.R.. SLick on yhe dymanic range tab here:
http://dxomark.com/index.php/eng/Image-Qua.../(brand3)/Canon (http://dxomark.com/index.php/eng/Image-Quality-Database/Compare-cameras/(appareil1)/304|0/(appareil2)/318|0/(appareil3)/305|0/(onglet)/0/(brand)/Phase%20One/(brand2)/Phase%20One/(brand3)/Canon)
What's the reason for the decrease in DR as the ISO increases as can be seen over at DXOmark? IT looks like as soon as you hit ISO 100 or above the DSLRs win in terms of D.R.I don't know how they arrived at this result. However, the P45 Plus DOES have analogue ISO up to 800, at least I don't see any sign of digital manipulation. On the other hand, analogue supported ISO does not necessarily mean any noise reduction. For example the 5D2 has analogue gain up to 3200, but the loss of dynamic range from 1600 to 3200 is a full stop, because the analogue gain of 3200 is ineffective, compared to 1600.
Not for low ISOs, but most owners beleive it can. See a very technical study (http://www.cryptobola.com/PhotoBola/SonyA900/SonyA900_NR.htm) of this topic (although I thought you had seen this on GetDPI).
P65+ just received the highest score at dxomark.com database
beating ptevious leader Nikon D3x.
Interesting! What I see from the graphs is that the D3X still trounces the P65+ with regard to dynamic range. In fact, the only advantages of the P65+ that are apparent in the DXOmark results are better noise, better tonal range and better color sensitivity, at base ISO only and on a small print (8"x12").
Minor addition: what we see is that DxO's measurements of DR still have the D3x come out on top. I have not yet heard of someone who has seen results from both who would agree with that, so all this points out is that how they measure it is not how we see it. In other words, the results are useless.
(2) The Canon 50D versus the Canon 5D in respect of noise and DR after ISO adjustment had been made to equalise DoF and shutter speed. (Ie. 50D at F4 and ISO 100, compared with the 5D at F6.3 and ISO 320)Ray, do you mind uploading one of the ISO 320 raw files? If you have one heavily overexposed (raw clipping), that would be great, but if not, then any one is ok.
Minor addition: what we see is that DxO's measurements of DR still have the D3x come out on top. I have not yet heard of someone who has seen results from both who would agree with that, so all this points out is that how they measure it is not how we see it. In other words, the results are useless.
Ray, do you mind uploading one of the ISO 320 raw files? If you have one heavily overexposed (raw clipping), that would be great, but if not, then any one is ok.
The subject matter isn't a good indicator of DR performance and there aren't any high ISO shots. However the full size files are available for download and comparison(some jpeg compression to fit flickr file size limitations). Hope this helps.
Even when both images are downsampled to an 8"x12" print size, which of course improves both the DR and noise of the P65+ to a greater extent than it does for the the D3XThis is plain rubbish. Downsampling does not increase the dynamic range the very least.
the D3X still retains a whopping 2 stops DR advantage at the 'real' ISO of 170, compared with the real ISO of 178 for the P65+I belive only that comparison, which I cooked myself (paraphrasing WSC).
This is plain rubbish. Downsampling does not increase the dynamic range the very least.
I belive only that comparison, which I cooked myself (paraphrasing WSC).
Without having seen any image created by P65 Plus, I risk saying, that this "2 stops DR advantage" is the the product of a comparison performed in drunken stupor.
This is plain rubbish. Downsampling does not increase the dynamic range the very least.
Without having seen any image created by P65 Plus, I risk saying, that this "2 stops DR advantage" is the the product of a comparison performed in drunken stupor.
The increased DR due to downsampling is only valid if you are willing to accept the simultaneous loss of resolution. If I'm going to buy a 60MP MFDB, I really don't care what its DR is at 8MP, I care about the DR at 60MP.I see two cases: those when the extra resolution is an IQ advantage and those where it is not. (Never mind that all my photography is in the second case when it come to 20MP plus sensors!)
The increased DR due to downsampling is only valid if you are willing to accept the simultaneous loss of resolution. If I'm going to buy a 60MP MFDB, I really don't care what its DR is at 8MP, I care about the DR at 60MP.
I have severe difficulties grasping the concept of increased DR with downsampling. So, suddenly detail appears in whites or blacks where there wasn't to begin with at a much larger resolution? Is there an explanation for this?The explanation is that the noise floor level that sets the bottom of the dynamic range is based on the level of random fluctuations of noise, it is not the minimum output level above zero. Merging multiple pixels into one larger one increases the signal in proportion to the number of pixel merged, but the total noise increases by less, as it is a mixture of positive and negative deviations from the "true" signal, so there is typically some cancellation of the noise from the different pixels. So the signal to noise ratio improves.
Standard signal theory says that if the noise at each of the merged pixels is independent, the noise in a super-pixel produced from N pixels is about sqrt(N) times the typical single pixel noise level, while the signal is N times greater, and so the signal to noise ratio and dynamic range increases in proportion to sqrt(N)Noise is not the only governing factor; in fact, this is the lesser issue. Our subject is photography; the dynamic range is not limited alone by noise but by detail reproduction as well. Or do you believe, that the dynamnic range of a camera can be increased by aggressive noise reduction?
Noise is not the only governing factor; in fact, this is the lesser issue. Our subject is photography; the dynamic range is not limited alone by noise but by detail reproduction as well. Or do you believe, that the dynamnic range of a camera can be increased by aggressive noise reduction?
However, image reduction destroys details. Therefor the decreased noise level is useless, except on clean, textureless surfaces - but that's, what noise reduction software can solve.
Noise is not the only governing factor ... the dynamic range is not limited alone by noise but by detail reproduction as well.You seem to be redefining "dynamic range" to suit your purposes. I was explicitly talking only about dynamic range, not some more general concept of image quality including "detail reproduction". Detail is another dimension of image quality, not at all a part of the meaning of dynamic range.
You seem to be redefining "dynamic range" to suit your purposes. I was explicitly talking only about dynamic range, not some more general concept of image quality including "detail reproduction". Detail is another dimension of image quality, not at all a part of the meaning of dynamic range.
Well, you've lost me here, ...
If the scene being photographed has a high SBR (say 15EV), the P65+ will not deliver better detail than the D3X in the deepest shadows, whatever the print size (assuming equal print size for the comparison, of course). This is what the statement, 'the D3X has better DR than the P65+', actually means in practiceYour interpretation of English sentences is remarkable. For me, the meaning of one camera will not deliver better detail than the other... is, that the one is not better in that setting, not the other camera is better.
Another interesting issue that emerges from these DXOmark results is the apparent huge discrepancy between the nominal ISO sensitivities of the P65+ and the real and actual ISO sensitivity, as measured by DXOYou stress the "equalization" so much, that you are prepared to degrade a 65Mpix camera to a 12Mpix (8x12 with the very high printing density of 360ppi). On the other hand, you are insisting to balance the ISO differences - how do you balance the resolution difference? Downsampling is not "balancing" but "obfuscating".
...
Anyone who wishes to do serious comparisons of these two cameras needs to take this issue into consideration
I am lost since ages, by all of you and related to this subject!
Thierry
You seem to be redefining "dynamic range" to suit your purposesYou seem to believe, that the current topic is engineering. In photography, both the noise and the detail reproduction are components of the image quality.
downsampling from 60MP Bayer CFA raw output to say a 24.5MP RGB format will have more image detail than 24.5MP Bayer CFA raw, so it is not so clear how to equalize image detail. Maybe downsampling to half or less the lowest sensor pixel count equalizes detail.Perhaps to the greatest common denominator? Let's downsample all images to one megapixel. P&S cameras are too welcome to participate in the shootout.
Your interpretation of English sentences is remarkable.
For me, the meaning of one camera will not deliver better detail than the other... is, that the one is not better in that setting, not the other camera is better.
Anyway, I don't see as proven, that the P65+ will not deliver better detail than the D3X in the deepest shadows. As of now, it is a claim, nothing else.
You stress the "equalization" so much, that you are prepared to degrade a 65Mpix camera to a 12Mpix (8x12 with the very high printing density of 360ppi). On the other hand, you are insisting to balance the ISO differences - how do you balance the resolution difference? Downsampling is not "balancing" but "obfuscating".
Back to the issue: the P65+ is not a walkaround camera. You would not make shots with that like your #9199 (the greek taverne) with your 5D. It will be used mostly in settings, where the illumination won't limit the exposure seriously. In other words, it will be used at its optimal setting.
I have only a Canon 40D, but the vast majority of my shots were made (not taken) at ISO 200 (or at ISO 100, only a tiny bit better than ISO 200), in order to utilize the maximum dynamic range. I would not waste a P65+ in settings, where it can not be utilized optimally.
Thus your (and DxO's) equalization of ISOs is a worthless excercise, waste of breath and bandwidth.
This is an hilarious thread (and entertaining). And I mean no disrespect to those posting... but... (and I'm sure this has been said many times before)... one doesn't need Dx0 or on-line measurebating to determine if the P65+ or the D3x or Canon 5DII is best for one's needs. In fact, most of this (interesting) technical crap is so academic as to be at risk of influencing a decision into the wrong direction.
Demoing a P65+ is the obvious course for those considering it (or any other digital back) – not consulting Dx0 or any other similar site. I'll even submit that if one can't see the differences in the files, then there's no need to consider any of the new equipment. As Ray says "don't worry, be happy". Same goes for the D3x and others. Each can be rented or demoed. Charts, graphs, DR, do not determine the image. In fact, often a 10 or 12 stop image might be quite UNappealing in comparison to those with "sexy light" holding only six stops.
I own only the lowly, and much forgotten, P25+ (in my MF kit). I love it. I have compared the files to those of other cameras/backs and I still like it. Some cameras (or backs) best it, others do not. If I could afford it I would consider upgrading to something with higher pixel count, but not without significant consideration. It's the image, not the numbers. For my needs, a full-frame Phase One "P50+" with maximum exposure length of about five minutes, and 7µ pixel dimension, might be perfect (to facilitate making even larger prints). For my good friend (a working pro) the 5DII is a much better choice, another, the 1Ds3, etc.
The images simply do not LOOK the same from these different equipment. What's better or best? That depends on your needs and tastes. For example, for many DR has little importance once they learn what their equipment will record. That comes from... wait for it... ... taking pictures. As discussed, the sensor is part of it; the conversion software is part of it; the operator is part (much) of it.
All meant in fun, folks. I waited all these many pages before venting. We all have different needs and interests. I find that many people considering my images don't care about any of the stuff that we consider when we choose our backs, bodies, printers, etc. I always learn something from this type of thread, but perhaps not what some might expect or wish to "teach". I like the technical and theoretical discussions too (up to a point), but please let's not throw "photography" under the bus for "computing".
I know, I know... I stepped over the line, or at least, off-topic, by dragging photography in to this.
Best,
Dale
Demoing a P65+ is the obvious course for those considering it (or any other digital back) – not consulting Dx0 or any other similar site.
Dale
I have severe difficulties grasping the concept of increased DR with downsampling. So, suddenly detail appears in whites or blacks where there wasn't to begin with at a much larger resolution? Is there an explanation for this?
Also the idea of less noise with downsampling though I am willing to accept that sooner. It might be less visible but I am pretty sure the percentage of noise will be the same unless the downsampling is accompanied with noise reduction that tosses away bad pixels/noise first.
I think people are much too fixated on the notion of resampling images to a common size to discuss noise and dynamic range.
I think people are much too fixated on the notion of resampling images to a common size to discuss noise and dynamic range. The point is that noise is not a single number, it has a spectrum, it is a function of spatial frequency, just as the MTF of a lens varies with spatial frequency. Noise that is independent from pixel to pixel generates a noise spectrum that (after averaging over angular orientation) is linearly rising with spatial frequency. For instance, here are noise spectra of the Canon 40 (red) and 50D (blue):
http://theory.uchicago.edu/~ejm/pix/20d/po...epower-norm.png (http://theory.uchicago.edu/~ejm/pix/20d/posts/tests/Noise/40d-50d_noisepower-norm.png)
The 40D, with less resolution, cannot reach the highest spatial frequencies in line pairs per picture height available to the 50D; consequently its noise spectrum cuts off somewhat earlier. The pixel level noise is the area under the curve; since the 50D curve extends further, it has more pixel level noise. However, if we fix a scale by picking a particular spatial frequency that both cameras can reproduce, the noise is the same. The 50D is not a noisier camera than the 40D.
What does downsampling do? Proper downsampling simply removes all spatial frequencies above the Nyquist frequency of the target image, and chops off the portion of the noise spectrum above that frequency. I downsampled the 50D image to the 40D pixel dimensions, and this is what happened to the noise spectrum:
http://theory.uchicago.edu/~ejm/pix/20d/po...epower-norm.png (http://theory.uchicago.edu/~ejm/pix/20d/posts/tests/Noise/40d-50dresamp_noisepower-norm.png)
Red and Blue as before; Orange is the 50D downsampled with PSCS3 bicubic, black is downsampling with ImageMagick's Lanczos resampling. The downsampling, especially with Lanczos, quite faithfully reproduces the 40D noise spectrum. Of course, the downsampling also removed any image detail at spatial frequencies above the Nyquist frequency of the 40D.
However, one needn't have done the downsampling; it was enough to know that the noise power spectra have the same slope to know that the finer resolution camera is not noisier than its lower resolution cousin; one doesn't need to resample to compare noise, one simply needs to level the playing field by fixing a reference spatial frequency and comparing the noise there, much as one can compare MTF's of different lenses at a fixed spatial frequency to see how much detail they render. This is my interpretation of what DxO does in their "print" tab; they are implicitly choosing a spatial frequency by fixing an output size and doing a mathematically ideal resampling to a reference Nyquist frequency associated to that output size at a standard resolution in dpi (which translates to a given Nyquist in lph). The resampling is superfluous, all that matters is the comparison at a fixed spatial frequency.
Now, dynamic range is tightly correlated to noise; the technically savvy photographer's working definition of DR is the range of illumination levels having an acceptably large S/N in an image capture. Since noise is a function of spatial frequency, so is DR (BJL explained this in a somewhat more intuitive way). Again, downsampling does not increase DR; rather it is changing the spatial scale at which DR is being measured. DR at a fixed scale largely doesn't care about downsampling, just as the noise of the 50D at a fixed spatial frequency below the target Nyquist didn't change when the image was downsampled. To compare the DR of two cameras without fixing a common scale or spatial frequency at which to do the comparison, is a largely meaningless exercise. However, the finer resolution camera need not be downsampled to make the comparison, rather one needs to measure the dependence of DR on spatial frequency.
Dale,
If you consider that demoing a P65+ is the obvious course of action for those considering it, or any other digital back, is there any reason why such an approach should not apply to all cameras? If you think this is true, then, according to you, we could dispense with all technical tests of cameras and just rely upon word of mouth or simply adopt a 'follow the leader' approach.
[snip]...
Organisations like DXO who share their results with the public should be congratulated. Those who state that DXO results are a load of codswallop are merely displaying their scientific illiteracy. Perhaps they are proud of such illiteracy. Reading a graph is not that difficult, is it?
As for "demoing equipment", I have read your posts regarding MF vs FF DSLRs and how you don't buy into the process of shooting samples and deciding what's best based on one's observations (I apologize if I have incorrectly summarized your ideas here), and I must say that I don't buy it. But that's OK, again, our opinions differ.
I stand by my remark that putting too much trust in sites like Dx0 or other similar "tools" might lead one to a purchase one later regrets or at the least, does not understand. In my case, I have shot the tools that are reasonable considerations for my purposes; I can see the differences in each; and I have purchased what will work for me (within my budget). And before you say that I live where demoing is easy, I'll say that I live in a town of 12,000 people in which there is not one useful camera shop.
There are some real issues with the DxO measurements, but you ignore those.
When you were arguing with Gabor, you kept misrepresenting what he was saying, and then arguing against this modified version. In fact, he was just pointing out that considering only DR and ignoring resolution doesn't give useful information. You can use noise reduction software to increase *apparent* DR, but the loss in ability to reproduce detail won't make it worth the exercise to most people.
The DxO site lists three values and then gives a single summary number. I once set up three equations in three unknowns to figure out what the weights were (of the form Ax + By + Cz = D), and chose the Leica M8, Nikon D3 and Canon 1Ds3 or something like that, and one of the weights came out negative. DxO really needs to be more open about how they put together these numbers. They make ratings and claims but sometimes what they post makes no sense. If they were open about it, people could point out what doesn't make sense and what needs to be improved. As it is, you get a few numbers describing the cameras but you don't know what they mean, really. That isn't useful.
I have a 5D2 and a ZD. On DXO the 5D2 rates a tad higher than the ZD on everything at base ISO. But when I check out my photos taken at the same time, the ZD dynamic range feels much greater, especially in the shadows.
It feels like the ZD has many stops more dynamic range than the 5D2 but DXO doesn't show that.
Bill
I have a 5D2 and a ZD. On DXO the 5D2 rates a tad higher than the ZD on everything at base ISO. But when I check out my photos taken at the same time, the ZD dynamic range feels much greater, especially in the shadows.
It feels like the ZD has many stops more dynamic range than the 5D2 but DXO doesn't show that.
Bill
The 5D2 has substantial pattern noise (as do all Canon DSLR's, especially non-1 series).
My ZD has more DR than my 5D2. It looks rather obvious. I didn't try to test it by looking at numbers and so forth and if you do it takes a lot of effort I assume to do it right. And when you bring up the shadows in the ZD it works much better than the 5D2.
I was taking some difficult shots in a forest with directly sunlight on a face but the rest of the body in shadows. The ZD did quite well with the scene. The ZD feels more like a nice quality motion picture with the 5D2 feeling like a TV show video by comparison. That is sort of how I relate to it.
It is sad that the 5D2 has that pattern noise down bellow. I assume that doesn't show up with DXO.
I almost always use the ZD at ISO 50.
Bill
I stand by my remark that putting too much trust in sites like Dx0 or other similar "tools" might lead one to a purchase one later regrets or at the least, does not understand. In my case, I have shot the tools that are reasonable considerations for my purposes; I can see the differences in each; and I have purchased what will work for me (within my budget).
Unless you can show us 100% crops of the same scene with the same lighting, the same FoV and the same shutter speed, we can't be sure about the validity of your impressions. You need to expose your methodology for us to make an assessment, otherwise it's all speculation.
There are some real issues with the DxO measurements, but you ignore those.Quote from: RayCarstenw,
What are they? If you don't specify them, it's understandable I would ignore them. I'm not a mind-reader.
I've never ignored resolution. Check my posts again.
Is this the source of the confusion? The single number assessments under the 'overview' heading? If you are at all serious you will look at the individual graphs that detail performance at various ISO settings. The single numbers in the overview are weighted.
For example, it has been established by me, and later confirmed by DXOmark, (that sounds arrogant, but I did show my results first) that the D3 has approximately a 1/3rd to 1/2 a stop DR advantage over the 5D at high ISO. So how come there's such a huge difference in the single number rating for low-light ISO? The D3 is rated at 22.9 and the 5D at 13.68. That's a huge difference. It doesn't seem to corelate with the graphic results under the DR heading. What does DXO mean by the expression 'low-light ISO'? It clearly doesn't mean, 'high-ISO performance'. I've got no idea what subjective elements have influenced these single number ratings. I recommend ignoring them.
Unless you can show us 100% crops of the same scene with the same lighting, the same FoV and the same shutter speed, we can't be sure about the validity of your impressions. You need to expose your methodology for us to make an assessment, otherwise it's all speculation.
It's too much work for me to setup such a comparison. But perhaps I will if I have some free time this 3day weekend. Currently you have a subjective testimonial that Bill says the ZD has more DR than the 5D2 especially in the shadows. Easton the car photographer also said the same thing a while back.
It is imaginable, that the ZD had greater DR than the 5D2, though it is improbable. However, Bill said :-) It feels like the ZD has many stops more dynamic range than the 5D2 but DXO doesn't show that , and I dear say flatly, that this is not so.
Pls keep in mind, that the ZD creates only 8 levels for the tonality over the 9th stop of the DR. Theoretically, if the noise is very-very low, one could say there are four levels for the 10th stop, two levels for the 11th stop, and one level for everything above. In other words, if the sensor of the ZD were so good, the ZD would be bit depth challenged, like the 5D classic.
The 1D3 only has about 11.7 stops of DR at the pixel level; 14-bit tonal depth is wasted on itOn what criterion is this figure based on?
The single-most damning flaw is that they don't publish their exact process, so that their numbers are only black magic to others.
I didn't say that you did. I said that Gabor was saying that resolution was important.
Man, you are one of the worst readers I have ever seen! What do you think I set up three variables in three unknowns for? I even said so: to find out what the weights are. The weights made no sense, and it throws even more doubt onto their claims when one can't even figure out how they combine their three individual ratings into their one final rating.
I'll go back and figure out the rating weights again, and see if they have fixed anything.
On what criterion is this figure based on?
... I think it really comes down to the fact that a lot of people were lied to by the DB makers for years(eg - fake ISOs above ~400) ...
I think it really comes down to the fact that a lot of people were lied to by the DB makers for years(eg - fake ISOs above ~400) and don't want to deal with the results of the bit camera makers' DSLRsKeep in eye, that DSLR manufacturers are doing the same, with the same success. Read the diverse forums and see, how many owners believe to shoot with ISO 6400 and above with the 5D2, 12800 and 25600 with the D3, etc., while they are in fact only underexposing.
I think it really comes down to the fact that a lot of people were lied to by the DB makers for years(eg - fake ISOs above ~400) and don't want to deal with the results of the bit camera makers' DSLRsDx0 is good for at least that much in any case, because it clearly shows glitches and lying. For example:I'm afraid DxO is wrong in this case (too). According to the few P45+ files I have, the higher ISOs are *not* fake. I wonder if they saved the cost of renting a camera for test purposes, thinking that the P45 Plus is acting like the P45.
http://www.dxomark.com/index.php/eng/Image...se-One/P45-Plus (http://www.dxomark.com/index.php/eng/Image-Quality-Database/Phase-One/P45-Plus)
Click on the ISO Sensitivity tab. Whatever their testing methods, there plainly is something the maker isn't telling us going on.
There might be information which doesn't come accross, there might be information that is not understood, there might be information that is not explained, there might even be information which is not given, because not relevant, but to say that digital back manufacturers are lying and purposely lying to their customers or potential customers is a serious accusationThierry, forget about the term used by Plekto, let's deal only with the factual background.
Max engineering DR at ISO 200; 5 ADU read noise out of 16383 max signal. 16383/5~11.7 stops.How do you calculate it for Nikon cameras?
I'm afraid DxO is wrong in this case (too). According to the few P45+ files I have, the higher ISOs are *not* fake. I wonder if they saved the cost of renting a camera for test purposes, thinking that the P45 Plus is acting like the P45.
Although indications are one can go pretty far down and have usable pictures, it would seem that ISO 1600 is better reached by underexposing ISO 100 than by underexposing from ISO 400.
How do you calculate it for Nikon cameras?
How do you reconcile the above statement with the following statement from Emund Ronald about the high ISO performance of his new P45+?I don't. However, it seems (as far as I can measure it from the few raw files I have), that the higher ISOs of the P45+ could be fake with the same result, i.e. increasing the ISO does not reduce the noise. Like ISO 3200 with the 5D2: it is not fake but useless, except for JPEG (one could say it is an analog fake, while 6400 is fake analog .
For the read noise, one can either access the masked pixels and look at their std devBut they don't record any (except for the D300). Did you think I asked specifically the Nikons by chance?
or fit a straight line to the noise variance vs exposure, whose intercept is the read noise variance (take the sqrt to get the std dev). For the latter method, it is best to take differences of pairs of raw files in order to eliminate systematic errors.I find this not reliable enough even with the latter method, particularly with 12bit depth. A small difference in the "read noise" causes a large difference in the engineering DR.
DXO are in the business of marketing their own RAW converter. I imagine that the exact processes they use to get their measurements will be patented. The'tool' they use to get their measurements is called a "DXO Analyzer". The information they gather about a sensor is crucial to the design of their RAW converter. Do camera manufacturers publish full details of their sensor technology? C'mon! Be sensible!
Everyone reading this thread knows that resolution is important.
It won't necessarily help you if you figure out the rationale behind their weighting, or the algorithm used to determine a single-figure value. The essential point about a weighting process is that there is a subjective opinion at its core. If you discover the method by which they arrive at those single-figure assessments, you will at least be in a position to determine if DXO are consistent in the application of their ratings, but you may disagree completely with the subjective decision behind their approach.
If you think any of their figures (apart from the subjective weightings) are way out, please demonstrate the fact and provide the evidence. That's not too much to ask is it?
Thierry, forget about the term used by Plekto, let's deal only with the factual background.
The eMotion 54 LV is said to have ISO up to 400, according to you in an earlier post. However, the fact is, that the e54 does not have different ISOs at all; ISO 100 and above are plain underexposures, and the so-called ISO is nothing more than metadata telling to the raw processor to boost the intensity. Many customers (I dare say the vast majority of the customers) don't know this. Don't you think that if they knew this, they would be more conservative in their using of ISO 100 and above?
But they don't record any (except for the D300). Did you think I asked specifically the Nikons by chance?
I find this not reliable enough even with the latter method, particularly with 12bit depth. A small difference in the "read noise" causes a large difference in the engineering DR.
Are you sure about this? Bill Claff's Nefutil programHow do you think Rawnalyze could display an image without my knowing about the masked pixels?
http://home.comcast.net/~NikonD70/Download...til/NefUtil.htm (http://home.comcast.net/~NikonD70/Downloads/NefUtil/NefUtil.htm)
uses the masked pixels to evaluate read noise
Keep in eye, that DSLR manufacturers are doing the same, with the same success. Read the diverse forums and see, how many owners believe to shoot with ISO 6400 and above with the 5D2, 12800 and 25600 with the D3, etc., while they are in fact only underexposing.
Thierry, forget about the term used by Plekto, let's deal only with the factual background.
The eMotion 54 LV is said to have ISO up to 400, according to you in an earlier post. However, the fact is, that the e54 does not have different ISOs at all; ISO 100 and above are plain underexposures, and the so-called ISO is nothing more than metadata telling to the raw processor to boost the intensity. Many customers (I dare say the vast majority of the customers) don't know this. Don't you think that if they knew this, they would be more conservative in their using of ISO 100 and above?
I think it really comes down to the fact that a lot of people were lied to by the DB makers for years(eg - fake ISOs above ~400) and don't want to deal with the results of the bit camera makers' DSLRs. It's not like Sony is a tiny company, after all. One would expect the giants to eventually overtake the small DB makers or come very close - and for less cost, too. If for no other reason than market share and advertising, which allows them to sell 10x as many units.
This happens in every case. Take the Audi R8. It's a mainstream auto maker that suddenly has a car that's nipping at the heels of the Ferrari and similar boutique cars. Well, it's not too surprising if you think about just their R&D budget and number of employees.
Dx0 is good for at least that much in any case, because it clearly shows glitches and lying. For example:
http://www.dxomark.com/index.php/eng/Image...se-One/P45-Plus (http://www.dxomark.com/index.php/eng/Image-Quality-Database/Phase-One/P45-Plus)
Click on the ISO Sensitivity tab. Whatever their testing methods, there plainly is something the maker isn't telling us going on.
If on the other hand one is using sufficiently clean electronics that the entire DR of the sensor is digitized with ample bit depth, there is absolutely no reason why one needs to use separate hardware gains for each ISO; the entire DR that the sensor is capable of is already captured, so one is not going to get anything more than that by changing the gain in the hardware. Higher ISO is underexposing the sensor no matter what, in the sense that the max signal falls far below the well capacity of the photosites. If the DR of the ADC sufficiently exceeds the DR of the sensor, it is irrelevant whether the amplification of that low signal is done in the analog or the digital domain. In fact, it is better to do it in the digital domain, since one isn't throwing away highlight information that the sensor captured by amplifying it beyond the range of the ADC, which is what hardware-based higher ISO gain does.
If MFDB manufacturers are using sufficiently high quality components that they don't need to use hardware based ISO gain, good for them; it means that they are getting the most out of their sensor. It looks like this is the case with the P45+ above ISO 100, based on the link to DxO. I wish Canon/Nikon would do the same, then they could unlock the 14 stops of DR that their sensors seem to be capable of, and that their amplifier/ADC's can't so far deliver.
That's an excellent point to make, Emil. However, the DXO results would suggest that neither the P45+ nor the P65+ is using sufficiently clean electronics to match the lower loss of DR, as ISO is increased, that is apparent with the D3X. How do you get the impression that this is not the case?
For example, at base ISO, the D3x has a full stop better DR than both the P45+ and P65+ (slightly more than a full stop, but let's not quibble).
At ISO 800, the D3X has a full 2.5 stops greater DR than the P45+. Nikon's analog, pre-A/D boost, is having the desired effect.
Here's the DXOmark link to the graphs I'm looking at.
http://www.dxomark.com/index.php/eng/Image...d3)/Phase%20One (http://www.dxomark.com/index.php/eng/Image-Quality-Database/Compare-cameras/(appareil1)/304%7C0/(appareil2)/287%7C0/(appareil3)/318%7C0/(onglet)/0/(brand)/Phase%20One/(brand2)/Nikon/(brand3)/Phase%20One)
Edit:I forgot to mention for the benefit of those who never get past the single figure "Overview". Click on the 'Dynamic Range' heading.
I didn't say their DR was better at base ISO, I simply said that they are getting close to the full DR of the sensor they are using.
Emil,
Reading your explanation, I get the impression that it would be possible for Nikon in a future upgrade to the D3X, to use more expensive, more robust, heavier duty and lower noise A/D converters and other components in the processing chain, to produce a DR result which would be 2.5 stops greater than the P45+ at base ISO as well as at ISO 800. (Although, after the furore regarding the price of the D3X, Nikon might be having second thoughts about an even more expensive upgrdade employing more expensive components. That's unfortunate for Nikon users I guess, but serves them right )
Can you confirm that this is essentially what you are saying? Because, if you are, that's quite amazing.
Reading your explanation, I get the impression that it would be possible for Nikon in a future upgrade to the D3X, to use more expensive, more robust, heavier duty and lower noise A/D converters and other components in the processing chain, to produce a DR result which would be 2.5 stops greater than the P45+ at base ISO as well as at ISO 800.
The D3X uses a Sony EXMOR sensor whose output is already digital, with ISO gain amplification and A/D conversion done on-chip at the bottom of each column of pixelsIs this the very same sensor, which is used in the Sony A900? If so, why does the A900 create only 12bit raw data, while the D3X creates 12 or 14bit?
So if the manufacturer were able to maintain that read noise at low ISO, the ISO 100 DR would be four stops more than the ISO 1600 DR, assuming that the well capacity is not exceeded at RAW saturation at ISO 100 (full well is slightly below RAW saturation on Canons at ISO 100, so one wouldn't quite get four stops, more like 3.8-3.9).
Emil Martin seems to believe that the A/D convertor is the main noise villain in Canon SLR's, but his evidence does does favor that hypotheses over my proposal about on-chip ISO gain amplifier noise. [Edit: Emil talks in this thread about combined amplifier/ADC noise, and I have no disagreement with that; his analysis both here and with the relationship between spatial resolution and DR is the best technical input we have in discussions like this.])
The idea of amp. noise as a major dark noise source can explain the slower degradation of DR and noise levels with increasing ISO speed with modern types of CMOS sensors than with CCD's, due to CMOS sensors applying gain earlier, and so better protecting the weaker signals at higher ISO from some noise sources, like noise during transportation across edge of the sensor.
a hobbled video capacity with limited manual control. There has to be something better on the horizon.Like a firmware update, to be released on 2009-06-02?
Like a firmware update, to be released on 2009-06-02?
That's news to meReally? Your complaints were decisive in the development.
What are the details?
Really? Your complaints were decisive in the development.
I'm a bit worried about that rather poor DR at base ISO, though. I might have to take my D700 along as well.How do you see the DR of your 5D?
How do you see the DR of your 5D?
Fourthly, whilst the DR at base ISO is not significantly worse than that of the D700, I'd be a bit concerned about the waterproofing issue with the 5D2 that became apparent on Michael's recent Antarctic trip.The DR of the D700 with ISO 200 is 1/2 EV better than that of the 5D2 with ISO 100. If you have to go with ISO 200, the difference is 2/3 EV.
Is this the very same sensor, which is used in the Sony A900? If so, why does the A900 create only 12bit raw data, while the D3X creates 12 or 14bit?The answer seems not to be public information.
One proposed explanation is that the A/D convertors do repeated sampling and averaging to reduce the RMS noise level. This goes with the lower frame rate in 14-bit mode (am I right that the D3X has a far lower frame rate in 14-bit mode?)I heard this speculation, already regarding the D3. However, there is a problem with it: analysis of the raw data shows, that the 14bit data is the "natural" version and the 12bit data is digitally derivated from the 14bit. The same is true re the D3X.
I heard this speculation, already regarding the D3. However, there is a problem with it: analysis of the raw data shows, that the 14bit data is the "natural" version and the 12bit data is digitally derivated from the 14bit. The same is true re the D3X.
I think the question is logical: if Sony is making such a sensor, why don't they make use of it?
What does downsampling do? Proper downsampling simply removes all spatial frequencies above the Nyquist frequency of the target image, and chops off the portion of the noise spectrum above that frequency. I downsampled the 50D image to the 40D pixel dimensions, and this is what happened to the noise spectrum:
http://theory.uchicago.edu/~ejm/pix/20d/po...epower-norm.png (http://theory.uchicago.edu/~ejm/pix/20d/posts/tests/Noise/40d-50dresamp_noisepower-norm.png)
Red and Blue as before; Orange is the 50D downsampled with PSCS3 bicubic, black is downsampling with ImageMagick's Lanczos resampling. The downsampling, especially with Lanczos, quite faithfully reproduces the 40D noise spectrum. Of course, the downsampling also removed any image detail at spatial frequencies above the Nyquist frequency of the 40D.
However, one needn't have done the downsampling; it was enough to know that the noise power spectra have the same slope to know that the finer resolution camera is not noisier than its lower resolution cousin; one doesn't need to resample to compare noise, one simply needs to level the playing field by fixing a reference spatial frequency and comparing the noise there, much as one can compare MTF's of different lenses at a fixed spatial frequency to see how much detail they render. This is my interpretation of what DxO does in their "print" tab; they are implicitly choosing a spatial frequency by fixing an output size and doing a mathematically ideal resampling to a reference Nyquist frequency associated to that output size at a standard resolution in dpi (which translates to a given Nyquist in lph). The resampling is superfluous, all that matters is the comparison at a fixed spatial frequency.
Now, dynamic range is tightly correlated to noise; the technically savvy photographer's working definition of DR is the range of illumination levels having an acceptably large S/N in an image capture. Since noise is a function of spatial frequency, so is DR (BJL explained this in a somewhat more intuitive way). Again, downsampling does not increase DR; rather it is changing the spatial scale at which DR is being measured. DR at a fixed scale largely doesn't care about downsampling, just as the noise of the 50D at a fixed spatial frequency below the target Nyquist didn't change when the image was downsampled. To compare the DR of two cameras without fixing a common scale or spatial frequency at which to do the comparison, is a largely meaningless exercise. However, the finer resolution camera need not be downsampled to make the comparison, rather one needs to measure the dependence of DR on spatial frequency.
Thus far in this thread, I have seen no mention of the Sensor+ (http://www.phaseone.com/Content/p1digitalbacks/Pplusseries/SensorPlus/SensorPlus2.aspx) pixel binning feature of the new Phase One P65 architecture. If one downsamples 4:1 by pixel averaging, the signal to noise improves as the square root of the downsampling ratio, or by 2:1. However, with the Sensor+ technology (which must be done on chip), 4 pixels are combined into one super-pixel which can be read with only one read noise, resulting in an improvement in the S:N of 4:1. Software downsampling would involve averaging of 4 pixels with 4 read noise contributions.
I would think that dynamic range would be improved, but Phase One claims a DR of 12.5 stops for both methodologies, but the ISO is quadrupled in the Sensor+ mode. I would think that the individual pixels would behave similarly whether or not binning is employed and that the ISO required for saturation of the pixels would not change. Does this mean that full well is not reached with Sensor+? How does binning affect the slope of the noise power spectrum?
... with the Sensor+ technology (which must be done on chip), 4 pixels are combined into one super-pixel which can be read with only one read noise, resulting in an improvement in the S:N of 4:1.That sounds right as far as the dark noise arising from transportation, amplification, and A/D conversion, but not photosite noise (dark current?). But these are probably the dominant sources of dark noise, so gaining about two stops of DR at equal ISO speed seems reasonable.
I would think that dynamic range would be improved, but Phase One claims a DR of 12.5 stops for both methodologies, but the ISO is quadrupled in the Sensor+ mode.Roughly, quadrupling ISO removes two stops of DR because the signal strength is reduced by 1/4 while the dark noise level stays the same, so it makes sense that the effects on DR of 4-1 binning and quadrupling of ISO balance out. There should be a DR gain at equal ISO speed (400 or higher) with and without binning.
The D3 is a totally different sensor design, for which it would be natural for 14 to be the native bit depth. Do you have evidence that this is so for the D300 and D3x? The RAW files I have for the D300 suggest otherwise; they have no gaps or spikes in the G channel.All the Nikon CMOS behave mostly the same way; this includes some pecularities as well. The D300 is different only in the handling of the green channels. There are no spikes in the 12bit version of a channel, because the numerical range is divided by exactly four.
IMO the combination D700 and 50D is optimal: one for the DR and clean image, the other for the reach.