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Messages - dtaylor

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31
EOS Bodies / Re: Are These The EOS 7D Mark II Specifications?
« on: August 23, 2014, 07:51:37 AM »
The IR method has a lot more variables and they don't test RAW they test after conversion RAW with cooked in NR of various who knows what degrees

NR does not affect total DR. And they use ACR with default settings for ALL cameras.

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(and that also explains how they manage to get this type of DR to actually measure higher than engineering DR measurements of the RAW file).

If DxO was measuring what you think they are measuring then this would be impossible no matter what processing was performed.

Go take a long, hard look at jrista's processing of the infamous 5D3 vs. D800 online test. DxO claims that there is a 2.5 stop DR difference between these two cameras. If that were the case then that door and those tiles in the far back should be BLACK. No detail or image at all in those regions, just blocked up shadow.

Instead we see the same features that we see on the D800, just with a lot more color noise.

The color noise impacts our ability to push the shadows, or shadow latitude. But the DR is darn near the same. It certainly is not 2.5 stops less.

There is your direct, observational evidence that DxO is wrong.

Perhaps more importantly for someone buying a camera, the final result with NR shows just how small the difference ends up being in the real world. Yes, the D800 is better. Could you spot it on a 36" print? Probably, but it certainly would not ruin the print. 24"? Most people could not without being told to look for it up close. 12"? Nope.

How often do you shoot a scene intended for 36" prints yet blow the exposure so badly that you need to push shadows this hard?   :o

32
EOS Bodies / Re: Are These The EOS 7D Mark II Specifications?
« on: August 23, 2014, 07:25:46 AM »
Actually I found out how. IR is measuring after raw conversion and NR has been applied!

NR does not affect how many steps of gray appear between black and white on a step wedge or total DR. It WOULD affect tests against arbitrary noise thresholds for "quality DR."

BTW: they use default settings for ALL cameras.

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Yeah and DxO is more direct,

Black box formulas are not "direct."

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And ironically enough it turns out that the DxO measurement didn't fail and that there is an explanation for the IR result,

Try photographing a step wedge some time. Keep increasing NR until more black squares turn gray  ::)

33
EOS Bodies / Re: Are These The EOS 7D Mark II Specifications?
« on: August 23, 2014, 07:10:47 AM »
Well, here's what the IR says about dynamic range.

I like that they use(d) Imatest and a step wedge. That yields an accurate, tamper resistant view of total DR. But I don't care what their opinion is on the definition of DR. The definition was solved before Ansel Adams!

Latitude...which is what you are actually talking about...is important to. But if it's as important to you as people pretend it is in online forums, then you are not exposing correctly, and quality will suffer even with Exmor. Exmor > Canon, but dealing with the scene (GND filter; HDR) will blow both away.

In practice if you are digging deeper then about 2...2.5 stops into shadows for detail then you are sacrificing tonality and micro contrast with any sensor. Canon can handle that about as well as Exmor just using the NR sliders in ACR.

34
EOS Bodies / Re: Are These The EOS 7D Mark II Specifications?
« on: August 23, 2014, 07:03:42 AM »
Your being rather misleading. This is what the article says:

I am not being misleading. IR does not specify what "highest quality" DR means, nor do they provide images to demonstrate. You and I both know the threshold is arbitrary and the result would be impacted by NR and processing (as you just demonstrated with the infamous D800 / 5D3 test above).

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I am not exactly certain how they do these tests or how they are calculating dynamic range,

They are photographing a step wedge and feeding it to Imatest. Preprocessing would change the result for "highest quality", but the total is pretty much the total. Again we're crossing the line from discussing DR to actually discussing shadow latitude.

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but they are pretty clear that when it comes down to QUALITY

Which they neither define in real world terms nor illustrate with real world samples, so it's pointless to debate.

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Even at low, the 70D scored 11.7 stops, and at medium it was 10.8. Those numbers seem more in line with what other sites measure.

What other sites? DPReview only does JPEG now, not ACR best, and DxO doesn't agree either way. (You can't cherry pick the "high" setting for Canon and the "low" setting for Nikon.)

I've worked with Canon, Nikon, and Sony RAWs and I can tell you with certainty that there is not a 2 stop difference in DR. They both fade to white and black at about the same points. What is different is how far you can push shadows due to noise vs. the work you want to put into the processing. Even with work if you push hard the final result is better with Exmor. But it doesn't matter nearly as often as Exmor fans pretend, especially in print (vs. pixel peeping).

35
EOS Bodies / Re: Are These The EOS 7D Mark II Specifications?
« on: August 23, 2014, 01:00:40 AM »
Funny you mention Ansel Adams since I'd bet a lot of money that he'd be.... not on your side here.

Come back when you've read some of his work.

36
EOS Bodies / Re: Are These The EOS 7D Mark II Specifications?
« on: August 23, 2014, 12:59:27 AM »
it doesn't seem subtle to me

and how exactly is it that a bye the eye DR rating gives a higher score than an engineering rating which goes deeper in the noise floor than some eyes would like?

For the nth time...DxO is not measuring photographic DR. They are measuring sensel SNR, running those values through a 'black box' formula, and predicting DR.

Understand that direct observation always trumps theory and prediction. Always. Never the other way around. No matter how much math, effort, belief, or faith you put in a theory, nor how many so called 'experts' trust in the theory, direct observation always wins.

DxO measures sensel SNR and concludes that a 70D (for example) only has 11.6 stops DR. Someone photographs a step wedge and sees 13 stops between black and white. The question is not "how exactly is it that a bye the eye DR rating gives a higher score than an engineering rating"? No, the question is "where did the engineering testing, model, or rating fail?"

37
EOS Bodies / Re: Are These The EOS 7D Mark II Specifications?
« on: August 23, 2014, 12:50:34 AM »
The 70D is at 13 stops. There isn't room for "significantly better" DR with a 14-bit ADC.

Except that the 7D has 11 stops of DR, not 13 stops.

Except that I was talking about the 70D. It's a good guess that The 7D markII sensor will be at least as good as the most recent APS-C sensor from Canon.

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The D7100 and the Exmor sensors have 13 stops of DR.

13.3 to be precise.

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Canon is still stuck at 11,

EOS M 12.4 Total RAW
http://www.imaging-resource.com/PRODS/canon-eos-m/canon-eos-mA5.HTM

70D 13 Total RAW
http://www.imaging-resource.com/PRODS/canon-70d/canon-70dA5.HTM

Myths die hard, don't they.

38
EOS Bodies / Re: Are These The EOS 7D Mark II Specifications?
« on: August 23, 2014, 12:45:59 AM »
I used to prefer Photography DR until I couldn't find a consistent means of computing it.

Step wedge test.

39
EOS Bodies / Re: Are These The EOS 7D Mark II Specifications?
« on: August 23, 2014, 12:44:24 AM »
I'm not talking about DxO's reporting of DR, I'm talking about computing real well capacity and read noise from DxO's measurements.  DxO's interpretation of their own data is pretty much total crap, and I never visit their site.  But the raw measurements are useful if properly interpreted.

I don't disagree with this statement. The problem is that people go to their site and accept their DR and overall score values at face value.

40
EOS Bodies / Re: Are These The EOS 7D Mark II Specifications?
« on: August 22, 2014, 10:47:26 PM »
"Photographic DR" would likely be less than DR measured this way, for a simple reason - we don't usually tolerate image detail that's near or at the noise floor.

DxO overstates DR for sensors with noise below their arbitrary threshold, and understates it for sensors with noise above their arbitrary threshold (especially in light of RAW conversion NR).

Perhaps more importantly, they're not measuring detail or steps in either case. If you photograph a step wedge with two cameras and one has slightly less noise in some of the otherwise pure black steps, DxO will count those as more DR! This is why when they "normalize" an image to 8 MP they report more DR.

It's silliness created by hardware nerds and not photographers. Someone needs to send DxO a few Ansel Adam's books.

41
EOS Bodies / Re: Are These The EOS 7D Mark II Specifications?
« on: August 22, 2014, 10:35:32 PM »
Sony already dropped a crop camera with 79pt AF system (granted, not all cross-type, but still excellent by all accounts), 12fps burst, and a better sensor earlier this year for less than $1700.

Every time I've looked at user reports Sony's DSLRs could not keep up in AF tracking with Canon or Nikon bodies. Not the 7D, and certainly not the 1DX or 5D3.

It's not just point count. Many Nikon bodies have the same point count as the D3 or the D4. But talk to a Nikon shooter and the actual performance varies considerably. Didn't the D800 have the same "AF module" as the D4? I know a guy who will tell you straight out that it could not track like one. Not even close.

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There is no reason that Canon should be falling behind Sony of all companies.

Have you compared lenses?  ;D

At this point a "revolution" in sensor tech will require multiple layers (for DR or for color) or at least 16-bit ADCs and sensel characteristics to produce meaningful bits beyond 14. This is true for Sony as well. I got excited when the rumors were for a multilayer sensor. Now that it appears this is not the case, I expect incremental improvements.

42
EOS Bodies / Re: Are These The EOS 7D Mark II Specifications?
« on: August 22, 2014, 10:27:03 PM »
The "huge difference" you are referring to in 5D3 vs. D8x0 online tests is not DR per se (the 5D3 clips to black about the same time as the D810) but latitude: the ability to push shadows without image destroying noise.

which is also DR

Except for the part where it's not.

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and mostly importantly regardless of how you feel like defining terms...

I didn't define the terms. These are standard terms which were in use in the photographic industry long before I was born.

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And it's a "huge difference" which can only be seen by turning all NR completely off for the Canon sensor  ::)
yeah whatever sure

Try processing the files yourself sometime. When you intelligently use the NR sliders the difference is nothing like the drama tests. There is a difference, Exmor is better, but the difference becomes a more subtle one.

43
EOS Bodies / Re: Are These The EOS 7D Mark II Specifications?
« on: August 22, 2014, 09:39:14 PM »
Put another way the 1/3 stops difference between 70D and aps-c exmor sure doesn't match what ones sees with their own eyes when out taking photos or the huge difference between D810 and 5D3....

So we're going to draw conclusions from an entirely different format???

The "huge difference" you are referring to in 5D3 vs. D8x0 online tests is not DR per se (the 5D3 clips to black about the same time as the D810) but latitude: the ability to push shadows without image destroying noise.

And it's a "huge difference" which can only be seen by turning all NR completely off for the Canon sensor  ::)

44
EOS Bodies / Re: Are These The EOS 7D Mark II Specifications?
« on: August 22, 2014, 09:34:58 PM »
* DxO measures SNR which does NOT directly translate to photographic dynamic range.

DxO measures, but does not directly report, well capacity and SnR.

The method of determining DR from that is shown here:

http://sensorgen.info/Calculations.html

Great. That tells me what I already know. That they are not measuring or reporting photographic DR. And that there are formulas I would have to hunt down or reconstruct in order to verify their results. (Though I suppose that would be possible to do for anyone so inclined.)

Again, DxO DR measurements are nonsense.

45
EOS Bodies / Re: Are These The EOS 7D Mark II Specifications?
« on: August 22, 2014, 09:30:21 PM »
In the past, it was said this would have some special video features.  Seems like servo mode for video is something that the 70D already has, at least in part, and 1080p60 is certainly nothing close to "special" as it exists on earlier Canon compacts, so where are the special video features?

I'm a stills photographer so I don't really care either way, but...if Canon hopes to gain rather then lose market share in this segment of the video market they really need to have 4k. And stop relying on hackers to put in critical features (no offense to the amazing ML team).

This is more of a shock to me then the sensor. I would have loved to see a multilayer sensor leap, but I'm not one of the people who is going to shed a tear if the 7D2 "only" has a 70D or moderately improved 70D sensor. I'm not mesmerized by DxO and I know most of what people fight over online is meaningless in the real world.

With apologies to Ansel Adams: There is nothing worse than a slightly higher DR image with slightly less shadow noise of a fuzzy concept.

That said...if these are the specs I will likely spend my money on other things and not upgrade my 7D for a while. The specs are solid, just not enough above what I have right now for what I do.

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