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Author Topic: DxOMark Sensor Performance: Nikon vs. Canon  (Read 127003 times)

elflord

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Re: DxOMark Sensor Performance: Nikon vs. Canon
« Reply #270 on: October 16, 2012, 08:54:57 PM »
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Typical of the DxO defenders, your MO is name calling and begging the question and hoping no one calls you on it.

Please do show me where I "name called".

I don't give a pile of used dog food about your white point - black point definition of DR. I'm not trying to make my blacks blacker. I can do that with NR and levels adjustments. I care about real, usable photographic detail. Down sampling and 'normalization' does not magically create new detail.

That's the part you don't seem to get though -- if you really do believe that the same image should have the same DR whether you sample it at 40mpx or 10mpx, then the normalized version of the dynamic range gives the correct result.

Downsampling doesn't "create detail", but it moves the black point.

If you're debating the merits of DxO's screen vs print numbers, this is important.

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Re: DxOMark Sensor Performance: Nikon vs. Canon
« Reply #270 on: October 16, 2012, 08:54:57 PM »

elflord

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Re: DxOMark Sensor Performance: Nikon vs. Canon
« Reply #271 on: October 16, 2012, 08:56:58 PM »

Your side has offered its argument for the accuracy of normalization. Our side has shown the argument to be false. Your side's only response has been "uh...you don't know what you're talking about!"

Please feel free to post any unanswered "critiques"

Far from rebutting, it's not clear to me that you or jrista understand the implications of normalization, or the basic math behind benchmarking,  so aren't in much of a position to criticize it. 

LetTheRightLensIn

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Re: DxOMark Sensor Performance: Nikon vs. Canon
« Reply #272 on: October 16, 2012, 10:21:21 PM »
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* Exmor sensors do not have the amount of excess DR being claimed by fans or DxO.

false

Oh, well, you used the word false, I guess the debate is over  ::)

Where is your evidence or explanation? Look at the FM test. I tested the DR myself and got same results and so have others. Have you tested any of it yourself? Do you have an explanation for why DxO is wrong?

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It hardly means you toss your Canon body into the swamp and then bash it with a sledgehammer but it sure would be nice if Canon paid attention to DR having not improved it for more than half a decade now.

I've seen improvements over that time period. DPReview saw improvements.

On what? 5D3 has actually worse DR than the 1Ds3.

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DxO are not liars, just confused.

explain

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There is 1-2 stops difference at low ISO, not "more than 3."

real world, accounting for banding, I'd say D800 does more than 3 better than 5D3 and even ignoring banding it's more than 2.

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2. There you go again, along with Jrista, and not having a clue about how normalization works and spreading misinformation.

Your side has offered its argument for the accuracy of normalization. Our side has shown the argument to be false. Your side's only response has been "uh...you don't know what you're talking about!"

It has shown it to be false? Where? When?
And not that I want to go here, but you've finally gotten me partially to this point, and sure even the most brilliant are wrong at times, absolutely true, and I'm not saying who here and on the other forums is who, but there are not only engineers but theoretical physics PhDs and other such, including some who are world renowned, posting in some of these threads and on some other threads and.... not on your side on this.






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Whether or not the 5D4 has better DR has nothing to do with these stupid threads, and everything to do with their engineers. I have little doubt they are working on it.

Did you know that another division of Canon sent a patent for better DR to the DSLR division and got told to get lost, DR, what?, why? bye. Apparently they didn't even let their engineers look at it! So maybe they do need to be woken up.

Source?

A Canon employee (non-DSLR division) on another forum.



rpt

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Re: DxOMark Sensor Performance: Nikon vs. Canon
« Reply #273 on: October 16, 2012, 10:43:01 PM »
I'm sure that i'm a lot younger than most of you gentlemens but this discussion is becoming a real joke, some of you look like they are immatures 5 years olds arguing about who has the best quality tricycle. Come on. Do not go offtopic and try to be objective.
:)
Yeah! I know the feeling. I think deep down somewhere locked or suppressed is a human desire to "Fight. Fight. Fight. Fight. Fight...". Why do you think more than 25% of world money goes towards the Offence Department? Just breathe and let these guys slug it out. They will get bored in a few days and there will be silence - for a while until it starts again. It is cyclic. May be the moon or something has an effect on us...

Whenever I get bored, I read these boxing matches. Then when I get bored of them, I go off and see the fabulous pictures many members have posted. There are Gurus on this forum so the big deal is not to get involved in the crossfire and distill the information. Even on this thread with all the back and forth there are gems and I am not being sarcastic. Well enjoy! Be assured if it gets baser, CR will use muscle  :)

LetTheRightLensIn

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Re: DxOMark Sensor Performance: Nikon vs. Canon
« Reply #274 on: October 16, 2012, 11:08:37 PM »
I'm sure that i'm a lot younger than most of you gentlemens but this discussion is becoming a real joke, some of you look like they are immatures 5 years olds arguing about who has the best quality tricycle. Come on. Do not go offtopic and try to be objective.
:)
Yeah! I know the feeling. I think deep down somewhere locked or suppressed is a human desire to "Fight. Fight. Fight. Fight. Fight...". Why do you think more than 25% of world money goes towards the Offence Department? Just breathe and let these guys slug it out. They will get bored in a few days and there will be silence - for a while until it starts again. It is cyclic. May be the moon or something has an effect on us...



It's not about fighting. It's debating and getting things straight. And if someone says stuff that is wrong and is trying to educate people by feeding them incorrect info, it is not fighting to point it out.

RLPhoto

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Re: DxOMark Sensor Performance: Nikon vs. Canon
« Reply #275 on: October 16, 2012, 11:46:41 PM »
your post is not even worth it to respond to, and Ansel Adams put a lot of work  in the copying as it is mention earlier

Ansel Adams wouldn't have missed his exposure by 10 stop's.  ::)

1. He would have if he was trying to show a quick, simple demonstration of the difference between two film stocks.
2. How many times does it have to be said that it's not even close to being all about fixing shots where something went wrong???

1. But, Not If he was planning to photograph anything worthwhile. He'd get his exposure right.

2. You yourself said it.


RLPhoto

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Re: DxOMark Sensor Performance: Nikon vs. Canon
« Reply #276 on: October 16, 2012, 11:50:32 PM »
I GET MY EXPOSURE RIGHT!

bollocks! ;D

you might be one of the lucky ones with a 7D that doesn't show as much FPN as others.
Wanna trade?  ;)

Malarky!  ::)

My 7D has the same sensor that DXO claims as garbage. It's no-where near as bad as others make it out to be, even though its getting older now.   8)

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Re: DxOMark Sensor Performance: Nikon vs. Canon
« Reply #276 on: October 16, 2012, 11:50:32 PM »

MarkII

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Re: DxOMark Sensor Performance: Nikon vs. Canon
« Reply #277 on: October 17, 2012, 02:21:39 AM »
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If you really think it is impossible then you should post the mathematical analysis that shows it to be so
No. Theory bends to observation, never the other way around.
Well, if I have a noisy image (ie with poor DR), it will be usable only at smaller print sizes than a less noisy one. That is a real world example of down-sampling, and if what you claim were true the small print would show exactly the same noise and DR than the larger one. Fortunately, this is not what we see in the real world!

As to the continued assertion that downsampling can not increase bit depth, consider a hypothetical one-bit sensor. I have two pixels, each of which can only take a value of 0 or 1. If I down sample by a factor of two, averaging pairs of pixels, I now have one pixel which can take values of 0, 1/2 or 1 and I now need more than one bit to store that pixel. I have traded-off resolution for improved dynamic range and I have more dynamic range than the original data (which you keep claiming is impossible).

It does not matter what the data is in this case - it just a basic property of the math.

If you do not think that this argument extends to a 14 bit file, I suggest writing out all the possible pixel values before and after downsampling from 22MP to 8MP and then work out how many bits of DR you have in the result...

So I say again, if you continue make the claim that DXO are "obviously wrong" because it is "impossible" to get pixel values with more than 14 bits of data after downsampling a 14 bit RAW file, explain why...

BTW, downsampling a 1 bit image is not an artificial example. Early monochrome printing relies on this technique. If you stand up close you see a noisy mess of dots. If you stand further away (making the image smaller - ie downsampling), you start to perceive the image as have graduated tones rather than just patches of plain white or plain black.

Tcapp

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Re: DxOMark Sensor Performance: Nikon vs. Canon
« Reply #278 on: October 17, 2012, 02:49:54 AM »
I GET MY EXPOSURE RIGHT!

bollocks! ;D

you might be one of the lucky ones with a 7D that doesn't show as much FPN as others.
Wanna trade?  ;)

Malarky!  ::)

My 7D has the same sensor that DXO claims as garbage. It's no-where near as bad as others make it out to be, even though its getting older now.   8)

I'm really not a fan of the 7d. I love its size, weight, feel, FPS, and AF, but the IQ is a little lacking at all ISOs. Just my 2 cents. It not bad but after using my 5d3 I don't touch it.
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tnargs

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Re: DxOMark Sensor Performance: Nikon vs. Canon
« Reply #279 on: October 17, 2012, 03:14:06 AM »
...As to the continued assertion that downsampling can not increase bit depth, ....

Is that the assertion? Or is the assertion that a 36 MP sensor with 13.2 bits of DR at 36 MP should be described as having 36 MP of resolution and 13.2 bits of DR?

MarkII

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Re: DxOMark Sensor Performance: Nikon vs. Canon
« Reply #280 on: October 17, 2012, 04:12:00 AM »
...As to the continued assertion that downsampling can not increase bit depth, ....
Is that the assertion? Or is the assertion that a 36 MP sensor with 13.2 bits of DR at 36 MP should be described as having 36 MP of resolution and 13.2 bits of DR?
No - the problem is people who assert that the DXO measurements are "obviously nonsense" because they (wrongly) believe that it is impossible for a down-sampled image to show more per-pixel DR than the original.

DXO use resolution normalised figures in their summaries partly because this is how most people tend to view their images (even the new 15" 'retina' MacBookPro screens are "only" 5MP at full-screen). And if they did not do this, some people would be screaming that they were biased because their numbers favour lower resolution cameras.

It is perfectly reasonable to describe a sensor as having ~13.2 bits at full resolution and ~14.3 bits at a normalised 8MP resolution. Anyone considering buying or using a device like this should be smart enough to understand what this means and take the time and effort to read beyond the headline summaries.

Do people really buy cameras because of one number in a test score? Do they only read the final summary table in a 20-page review before opening their wallets for thousands of dollars???  If so, they probably deserve what they get!

psolberg

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Re: DxOMark Sensor Performance: Nikon vs. Canon
« Reply #281 on: October 17, 2012, 04:48:34 AM »
Wow, site admin flip flops in dxo after saying he would never publish dxo numbers even if canon came ahead. Now it happened and we start to see dxo numbers.....now dxo matters :)

elflord

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Re: DxOMark Sensor Performance: Nikon vs. Canon
« Reply #282 on: October 17, 2012, 06:34:02 AM »
Is that the assertion? Or is the assertion that a 36 MP sensor with 13.2 bits of DR at 36 MP should be described as having 36 MP of resolution and 13.2 bits of DR?

Camera 1 has 36 megapixels and 11 stops of dynamic range per pixel, camera 2 has 20megapixels and 12 stops of dynamic range per pixel.

Which camera has more dynamic range if I display or print their images at the same size ? If I downsample the 36mpx image to 20mpx, I will get more than 11 stops of dynamic range, but do i get more than 12 ?

I think this is a pretty valid question, provided you intend to view the whole image on print or screen, as opposed to just viewing 100% crops.

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Re: DxOMark Sensor Performance: Nikon vs. Canon
« Reply #282 on: October 17, 2012, 06:34:02 AM »

TheSuede

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Re: DxOMark Sensor Performance: Nikon vs. Canon
« Reply #283 on: October 17, 2012, 11:09:30 AM »
I find it interesting that many would like to make it sound like an "underexposure" is the end of the world, and a photographical failure.

What that stance significates is failing to understand the implications. I spent quite a few years of my life fighting against this erroneous mindset when educating print and pre-press personnel starting out in their first stumbling steps of the "digital revolution". Back then, pre-press personnel was (if possible) an even more tradition-laden and anachronistic group of people than what photographers are today.

As someone mentioned Adams, I have to say that he is a person you really have to admire for the amount of energy and time he spent really getting to know his medium (film), and how you had to expose to get the most out of your envisioned image. He (as he worked with the physicists and chemists at Kodak) set up some really workable testing rules and also inspection criteria to be used when looking at image results.

And he always tried to get the exposure "right".

Now try to understand the implications the sentence in bold above sets. Getting an exposure "right" is NOT the same as trying to make 14-16% gray as you see the image conform to a certain photometric exposure at the film surface! And he never claimed that it was. If there is more pictorial detail that you want to emphasize in the end result (for him; film, development, print) in the shadows - you should really overexpose - compared to the baseline scene average exposure. And if there is "important detail" in the highlights, you need to underexpose [compared to the reference exposure]. He accepted that there was always a compromise between highlight, midtone and shadow local detail. I would recommend a visit to his old home, if his son still has the tours he used to. If you're nice, to him you might even get to see some "behind the scenes" notes and development plans - they're really impressive in attention to detail, and shows how much he mauled his negatives, using both over- and under-exposure, to get "what he wanted" out of them. Regional corrections of + or -3Ev was nothing out of the ordinary either.

In digital, the entire ramification of the process has changed.

Film has more latitude, but much less usable DR within a fixed scene
Film has an bell-shaped MTF modulus, digital is linear
Film clips and blocks gracefully towards both highlight and shadow; and
Digital clips hard against highlights and fades gradually into noise in shadows

This means that you can't treat digital like you did with film, and the most obvious differences are:
a) as long as the entire scene can be contained within the digital DR, you can put the raw-file related exposure (which is not the same as photometric exposure!) wherever you want - it does not effect internal detail contrast.
b) you have to mind the highlights (more) with digital - since when they're clipped, all internal detail contrast is GONE. Impossible to retrieve unless you let software guess what the clipped channel values should be from surrounding color information. This only works for about +0.5Ev from initial clipping.

To underexpose the raw file - again, this is not the same as the photometric exposure! - is the only practically available method to reign in the highlights in the scene. And this is also what Canon does with the "Highlight Tone Priority" or "HTP" option when you shoot jpg. The camera will underexpose the raw file, and then bring image midtone brightness up again - but with smother upper S-curve end of the brightness curve.

Underexposing an image that doesn't have any highlight areas (zones? maybe applicable) you want to protect though - that's only stupid. It hurts image quality.
« Last Edit: October 17, 2012, 01:57:58 PM by TheSuede »

LetTheRightLensIn

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Re: DxOMark Sensor Performance: Nikon vs. Canon
« Reply #284 on: October 17, 2012, 02:10:44 PM »
...As to the continued assertion that downsampling can not increase bit depth, ....

Is that the assertion? Or is the assertion that a 36 MP sensor with 13.2 bits of DR at 36 MP should be described as having 36 MP of resolution and 13.2 bits of DR?

It is described as that but when you want to do a relative comparison you can't compare cameras at different scales otherwise you are comparing noise power at two different frequencies as if they were the same.

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Re: DxOMark Sensor Performance: Nikon vs. Canon
« Reply #284 on: October 17, 2012, 02:10:44 PM »