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Author Topic: Canon EOS-1D X DXOMark Sensor Scores  (Read 35706 times)

elflord

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Re: Canon EOS-1D X DXOMark Sensor Scores
« Reply #75 on: October 13, 2012, 04:05:49 PM »
I mentioned this before, but perhaps it was lost in other conversation. My guess is that the 12.8 stops of DR for the 1D X is the "Print DR". It doesn't matter the camera, Canon, Nikon, or anyone else...I think that the Print DR figure is exceptionally misleading and falsely indicative of a sensor's capabilities. My guess is that the 1D X still only has 11.something stops of DR, like all the rest of Canon's cameras.

You keep repeating it, but it's still wrong. It's wrong because the low end of the dynamic range is determined by SNR, and SNR changes when you downsample. The lower end of the dynamic range is NOT some point at which the signal is clipped. It is not in general true that a pixel is completely insensitive outside the dynamic range. The baseline of dynamic range is defined in terms of SNR, not detectability.

You do run into a "quantization limit" at the number of bits in the ADC (assuming that both the sensor response and the ADC itself are linear), but even then, you do eliminate shadow noise and therefore increase your usable dynamic range.  But this is not an issue with the new canon bodies because their reported dynamic range does not exceed that of the ADC.

I should add further that  the screen "dynamic range" is also in some sense "just a score". A SNR of 0db is extremely noisy (as a point of comparison the powershot S90's noise at max ISO 18% gray is 13db), so depending on your criteria, the "usable dynamic range" might be a few stops less than that indicated by the screen score.

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Re: Canon EOS-1D X DXOMark Sensor Scores
« Reply #75 on: October 13, 2012, 04:05:49 PM »

jrista

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Re: Canon EOS-1D X DXOMark Sensor Scores
« Reply #76 on: October 13, 2012, 04:16:52 PM »
I mentioned this before, but perhaps it was lost in other conversation. My guess is that the 12.8 stops of DR for the 1D X is the "Print DR". It doesn't matter the camera, Canon, Nikon, or anyone else...I think that the Print DR figure is exceptionally misleading and falsely indicative of a sensor's capabilities. My guess is that the 1D X still only has 11.something stops of DR, like all the rest of Canon's cameras.

You keep repeating it, but it's still wrong. It's wrong because the low end of the dynamic range is determined by SNR, and SNR changes when you downsample. The lower end of the dynamic range is NOT some point at which the signal is clipped. It is not in general true that a pixel is completely insensitive outside the dynamic range. The baseline of dynamic range is defined in terms of SNR, not detectability.

You do run into a "quantization limit" at the number of bits in the ADC (assuming that both the sensor response and the ADC itself are linear), but even then, you do eliminate shadow noise and therefore increase your usable dynamic range.  But this is not an issue with the new canon bodies because their reported dynamic range does not exceed that of the ADC.

I should add further that  the screen "dynamic range" is also in some sense "just a score". A SNR of 0db is extremely noisy (as a point of comparison the powershot S90's noise at max ISO 18% gray is 13db), so depending on your criteria, the "usable dynamic range" might be a few stops less than that indicated by the screen score.

In the case of the 1D X, what you describe might indeed be the case. It is a bit different than the D800, wherein 14.4 stops of DR surpasses the bit depth of the ADC and the limit imposed by quantization. If we were purely talking about the Gaussian type of noise produced by the Poisson distribution of photons, I'd probably agree. I am not sure the same simplistic rules that apply to gaussian noise apply to the non-random forms of electronic/read noise, which is the primary cause of a LOSS of DR at low ISO in Canon sensors.

peederj

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Re: Canon EOS-1D X DXOMark Sensor Scores
« Reply #77 on: October 13, 2012, 07:51:31 PM »
Mikael,

FWIW, you're even more nuts.

Hugs and Kisses...  :-*

jrista

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Re: Canon EOS-1D X DXOMark Sensor Scores
« Reply #78 on: October 13, 2012, 08:31:31 PM »
The Canon  brand fanatics writes about   arguments regarding why something suddenly not important anymore (when "their" brand suddenly is not the best  ) this  take quite comical proportions ... Some very active writers, among others here at Canonrumors's are direct rabid - this despite the notice that they are intelligent enough to see the connections, there is an instinctive religious barrier that prevents them to see what's right in front of their eyes ... :-)


You might carry a bit more weight with your arguments if you actually posted facts, undoctored evidence, and did not resort to personal attacks. I have respect for elflord, even if I don't fully agree with his assessments (which I primarily do agree, I just disagree on some of the finer points, as do a number of others here).

You, on the other hand, well to be frank I don't have a shred of respect for you. I'd also point out my fanaticism isn't really about Canon. It is about DXO's scoring system and my general dislike of it, and the often unenlightened application of their scores by die-hard Nikon fanatics. ;P I apply my same skepticism for DXO's scoring in regards to Canon as I do in regards to Nikon (or any other brand, for that matter).

I'll freely admit that I greatly dislike the notion that simply because the D800 is a great camera, then all other cameras (and particularly Canon cameras) suck donkey danglers, and that the D800 is the end-all, be-all of cameras everywhere, infinitely capable of everything to everyone (a notion you would certainly think was true if you believed all the drivel from the majority of the raging Nikon fanbase). The advent of new & improved technology does not immediately and entirely negate previous technology, or diminish the quality it previously attained. The regular arguments to the contrary, and the bogus doctored, contrived or staged evidence to try and prove that bogus fact, are the fundamental basis of my tirade against such inanity. I've never disagreed that Exmor is some phenomenal technology, nor have I ever said Canon sensors do as well (although I certainly believe they can do as well or better, and probably will in coming Canon sensor generations). I simply deny that the difference between Canon cameras and Nikon cameras is as big as it is usually made out to be by the fanatical branch of the Nikonites. I also believe a periodic reality check to that fact is beneficial to those potentially...gullible enough?...to waste time, effort, and money jumping ship and switching brands when in most cases (there are a few outliers) it is unnecessary, and people could save their hard-earned cash.

jocau

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Re: Canon EOS-1D X DXOMark Sensor Scores
« Reply #79 on: October 14, 2012, 04:07:55 PM »
The 1D X scores still can't be found on the DXOMark website. 12,8 stops of DR out of a Canon sensor? I won't believe it until I see it.
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peederj

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Re: Canon EOS-1D X DXOMark Sensor Scores
« Reply #80 on: October 14, 2012, 04:30:47 PM »
The conspiracy theorists would suggest DxO is waiting the completion of "sponsorship negotiations" as to what the final score will be.  :o

LetTheRightLensIn

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Re: Canon EOS-1D X DXOMark Sensor Scores
« Reply #81 on: October 15, 2012, 12:29:10 AM »
I mentioned this before, but perhaps it was lost in other conversation. My guess is that the 12.8 stops of DR for the 1D X is the "Print DR". It doesn't matter the camera, Canon, Nikon, or anyone else...I think that the Print DR figure is exceptionally misleading and falsely indicative of a sensor's capabilities. My guess is that the 1D X still only has 11.something stops of DR, like all the rest of Canon's cameras.

You keep repeating it, but it's still wrong. It's wrong because the low end of the dynamic range is determined by SNR, and SNR changes when you downsample. The lower end of the dynamic range is NOT some point at which the signal is clipped. It is not in general true that a pixel is completely insensitive outside the dynamic range. The baseline of dynamic range is defined in terms of SNR, not detectability.

You do run into a "quantization limit" at the number of bits in the ADC (assuming that both the sensor response and the ADC itself are linear), but even then, you do eliminate shadow noise and therefore increase your usable dynamic range.  But this is not an issue with the new canon bodies because their reported dynamic range does not exceed that of the ADC.

I should add further that  the screen "dynamic range" is also in some sense "just a score". A SNR of 0db is extremely noisy (as a point of comparison the powershot S90's noise at max ISO 18% gray is 13db), so depending on your criteria, the "usable dynamic range" might be a few stops less than that indicated by the screen score.

In the case of the 1D X, what you describe might indeed be the case. It is a bit different than the D800, wherein 14.4 stops of DR surpasses the bit depth of the ADC and the limit imposed by quantization. If we were purely talking about the Gaussian type of noise produced by the Poisson distribution of photons, I'd probably agree. I am not sure the same simplistic rules that apply to gaussian noise apply to the non-random forms of electronic/read noise, which is the primary cause of a LOSS of DR at low ISO in Canon sensors.

advice:

just quit before you dig an even deeper hole on this issue  ;)

Elford has it right.

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Re: Canon EOS-1D X DXOMark Sensor Scores
« Reply #81 on: October 15, 2012, 12:29:10 AM »

thepancakeman

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Re: Canon EOS-1D X DXOMark Sensor Scores
« Reply #82 on: October 15, 2012, 02:48:35 PM »
The 1D X scores still can't be found on the DXOMark website. 12,8 stops of DR out of a Canon sensor? I won't believe it until I see it.

And that's what cracks me up about this whole thing.  If it were that significant or that drastic, you wouldn't need a test to tell you about it, you'd see it in the photos.  Just my $.02.   ;)

jrista

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Re: Canon EOS-1D X DXOMark Sensor Scores
« Reply #83 on: October 15, 2012, 03:30:58 PM »
The 1D X scores still can't be found on the DXOMark website. 12,8 stops of DR out of a Canon sensor? I won't believe it until I see it.

And that's what cracks me up about this whole thing.  If it were that significant or that drastic, you wouldn't need a test to tell you about it, you'd see it in the photos.  Just my $.02.   ;)

Well, it would only be visible in photos that were sufficiently downscaled, and downscaled in an appropriate manner with a proper algorithm that actually maximized the potential for DR gains. You would NOT see it in photos strait out of the camera (that goes for both D800 photos and 14.4 stops of DR as well as for the 1D X and 12.8 stops of DR), since Print DR is intrinsically dependent on proper downscaling.

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Re: Canon EOS-1D X DXOMark Sensor Scores
« Reply #84 on: October 15, 2012, 03:38:27 PM »
The Canon  brand fanatics writes about   arguments regarding why something suddenly not important anymore (when "their" brand suddenly is not the best  ) this  take quite comical proportions ... Some very active writers, among others here at Canonrumors's are direct rabid - this despite the notice that they are intelligent enough to see the connections, there is an instinctive religious barrier that prevents them to see what's right in front of their eyes ... :-)


Lol, and this is the same dude who didn't know that the nikon 51 Point AF hasn't changed much since last generation.  :-X

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Re: Canon EOS-1D X DXOMark Sensor Scores
« Reply #85 on: October 15, 2012, 04:26:06 PM »
I will still look at it, but learned a long time ago, nothing beats peoples real world hands on experience. I try to buy Lenses that way also. The 1d x is my 5th Digital in 12 years. Still have my old Minolta xg7. Relic like me...lol

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Re: Canon EOS-1D X DXOMark Sensor Scores
« Reply #86 on: October 15, 2012, 05:46:01 PM »
The Canon  brand fanatics writes about   arguments regarding why something suddenly not important anymore (when "their" brand suddenly is not the best  ) this  take quite comical proportions ... Some very active writers, among others here at Canonrumors's are direct rabid - this despite the notice that they are intelligent enough to see the connections, there is an instinctive religious barrier that prevents them to see what's right in front of their eyes ... :-)


Lol, and this is the same dude who didn't know that the nikon 51 Point AF hasn't changed much since last generation.  :-X

no , it is the same man who  wondering on which the basis and facts  Nikon's AF would be inferior to Canon
and  who never discusses AF because it would take a month to verify the results.
Your interpretation is therefore incorrect and based on your own conclusion

Ignorance is bliss for fanboi's like yourself.  ::)

Canon 61 pt AF > Nikon 51 pt AF. done.

dtaylor

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Re: Canon EOS-1D X DXOMark Sensor Scores
« Reply #87 on: October 15, 2012, 05:56:58 PM »
You keep repeating it, but it's still wrong. It's wrong because the low end of the dynamic range is determined by SNR, and SNR changes when you downsample.

This is the belief of a math geek who spends too much time with graphs and not enough time with real photographs. Down sampling throws away noise and detail. Dynamic range is the range of useful photographic detail. It is not the simple difference between two numbers on a graph.

Try this: shoot 4x5 Velvia. Drum scan it. Down sample to 10 MP. Did you all of a sudden gain 3-4 stops of shadow detail? No? Hmmm...

Side note: arguments like this are why I hate DR by software analysis. It has zero bearing on the real world. It just leads to paragraphs and paragraphs of irrelevant and pointless theorizing. Shoot a Stouffer transmission step wedge and look at it with your own two eyes. That tells you what you can expect in the real world.
« Last Edit: October 15, 2012, 06:03:09 PM by dtaylor »

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Re: Canon EOS-1D X DXOMark Sensor Scores
« Reply #87 on: October 15, 2012, 05:56:58 PM »

dtaylor

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Re: Canon EOS-1D X DXOMark Sensor Scores
« Reply #88 on: October 15, 2012, 06:15:53 PM »
Canon 61 pt AF > Nikon 51 pt AF. done.

Nonsense. Point count != superior AF. In my experience the 7D's AF is superior to the D7000's, practically on par with the earlier 45 point 1D bodies and several Nikon 51 point bodies, and it only has 19 points.

I don't honestly know who has the best AF right now because I don't spend sufficient time with the top tier bodies. But AF is an extremely complicated thing to objectively test, and subjective opinions are open to bias and error. AF performance can also be better on body A for situation 1, but better on body B for situation 2, etc, etc. Not to mention that lenses are at least as important as anything in the body, and it's a mistake to assume similar lenses from two manufacturers have similar AF.

Even with a case as one sided on paper as the 6D and D600 you can't conclusively say one body is always better than another. There's little point in discussing the top tier bodies unless you happen to own and shoot both regularly under a range of challenging conditions.

Fishnose

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Re: Canon EOS-1D X DXOMark Sensor Scores
« Reply #89 on: October 15, 2012, 06:17:34 PM »
Concerning all the discussions about whether or not 8Mp is a reasonable number for the 'print' scores:

DxO say "...high-resolution sensors will gain more SNR, DR, TR and CS when reduced to a lower reference resolution. For DxOMark Sensor Overall Score and Metrics, we chose a reference resolution equal to 8 Megapixels, which is a bit less than a 12" x 8" print with a 300dpi printer. However, any other resolution can be chosen, as doing so only shifts the normalized values by a constant (because the reference resolution appears only as a logarithm in the formulas above).
What should be remembered is that doubling the resolution adds:

    3dB to the normalized SNR
    0.5 bit to the normalized DR
    0.5 bit to the normalized TR
    1.5 bit to the normalized CS"

I'm guessing that at the time they chose 8Mp there were probably no cameras capable of anything over say 25Mp other than a couple of MF models. And many sensors were 8 or 12Mp. That's just a few years ago.

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Re: Canon EOS-1D X DXOMark Sensor Scores
« Reply #89 on: October 15, 2012, 06:17:34 PM »