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Author Topic: DR and RAW bit depth on Canon's forthcoming...  (Read 33994 times)

Flake

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Re: DR and RAW bit depth on Canon's forthcoming...
« Reply #15 on: February 26, 2012, 03:41:16 AM »
Reading some of these posts makes me think that there are some photographers who think it should be realistic to take photos of the setting sun and still keep details in the shadow areas!  Hardly any mention of HDR, and no mention at all of specialised filters.

Back in the days of film - and DR comparison of film and digital is incredibly difficult, companies like Lee & Cokin were producing the same filters as they are today.  That's photographic technique to improve the dynamic range, and even with the dynamic range improvements being mentioned on the thread, it's still not enough to negate the use of ND grads .

It also makes me wonder if this is a fault of the camera or the monitor?  Often I have images which appear to have a blown sky, and increasing exposure in PP of course makes it worse, but using the ND grad tool reveals that the camera has indeed captured all the detail in the sky, it's just that the exposure level needs to be reduced so it can be viewed.  Here is a piece from Wikipedia on the subject:

The most severe dynamic-range limitation in photography may not involve encoding, but rather reproduction to, say, a paper print or computer screen. In that case, not only local tone mapping, but also dynamic range adjustment can be effective in revealing detail throughout light and dark areas: The principle is the same as that of dodging and burning (using different lengths of exposures in different areas when making a photographic print) in the chemical darkroom. The principle is also similar to gain riding or automatic level control in audio work, which serves to keep a signal audible in a noisy listening environment and to avoid peak levels which overload the reproducing equipment, or which are unnaturally or uncomfortably loud.

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Re: DR and RAW bit depth on Canon's forthcoming...
« Reply #15 on: February 26, 2012, 03:41:16 AM »

Mt Spokane Photography

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Re: DR and RAW bit depth on Canon's forthcoming...
« Reply #16 on: February 26, 2012, 03:57:09 AM »
You don't need to do the Stoffer Wedge Test, its been done many times.  You can see the usable DR range of competiting camera bodies here:

5D MK II         8.4 EV
Nikon D700    7.8 EV

http://www.dpreview.com/reviews/CanonEOS5DMarkII/page25.asp

You can get more by manipulating RAW files, but the images tend to look flat and ugly.

I'd also like more DR, but, so far, no one seems to match film.

DPR test is ridiculous, it depends on nothing other than what tone curve is in the jpg setting.

You still get a tone curve processing in RAW.  you have to manulipate it to get a little more DR.  Then images tend to look flat.  DPR tells you the real world info.  Its like a statement of what you get off the showroom floor whan you buy a automobile, its what many, if not most get.

NoFitState

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Re: DR and RAW bit depth on Canon's forthcoming...
« Reply #17 on: February 26, 2012, 05:37:08 AM »
I'm really not that well informed on dynamic range.  Had a quick search for some examples of comparisons between Nikon & Canon and found this video.  I have no idea how indicative it is of the real world performance of both cameras, but its a fairly significant difference in my eyes.

http://testcams.com/blog/2011/05/03/nikon-dx-vs-canon-aps-c-dynamic-range/

Being able to just expose for highlights (and pull up the shadows in post) would make a big difference to some of the photos i've taken.  Really does seem like it should be higher on the priority list for a lot of us

Kernuak

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Re: DR and RAW bit depth on Canon's forthcoming...
« Reply #18 on: February 26, 2012, 06:17:07 AM »
I've said before, that lab tests are pretty meaningless, unless they reflect the real world, after all, as photographers, we are judged by what we achieve, not by what could be theoretically achieved. At work, we use analysers and I remember a number of years ago, I was working through a tender specification. The company supplying the analyser in question quoted a figure of 105 samples/hour throughput. When challenged, they said in reality, it averaged around 90 samples/hour. In reality, it is actually closer to 70-75/hour. It is very rare that any electrical or mechanical goods achieve theoretical values and the variation between reality and theory, is highly variable. Often, it is the equipment with the higher theoretical range, that is furthest from reality.
Flake mentioned the use of HDR and grad filters. As a landscape photographer, I know that even with an extra stop of DR, there is no way that I could capture most scenes without using grad filters, unless I make some compromises. In fact, photography is all about making compromises, that is what sets the greats apart from the merely good. If you could simply point a camera at a scene and get perfect results, then everyone would be doing it. The true masters, know how to manipulate the available light, to get near perfect results. Sometimes, you actually want blown areas for added effect, if you have a massive dynamic range that captures everything, how would you achieve that? Don't get me wrong, I would welcome more dynamic range, especially for wildlife, but I think we also have to be realistic and not accept suggested facts and lab tests too readily. The only sure way to make an accurate comparison, would be to shoot the same scene, with the same exposure value, at the same time, then look at the differences. The human eye is a precision instrument, it will detect meaningful differences if they exist. If it can't detect them, then they are irrelevant, no matter what tests tell you. It's not much use having an extra stop of DR, if your meduim of choice can't show it. I suspect that you'd need an expensive Spectraview type monitor to see any differences. Different papers will also have different DR, some papers have a higher DMax than others, allowing them to show more shadow detail.
A few years ago, I decided to have a play with slide film, as I'd never shot with it before, having only used negative film in the past. I did some digging at the time and was reading that slide film had a DR of around 5-6 stops, compared to 10-11 for negative film. My results with slide film clearly showed less DR than I could get with digital.
I did a bit more digging just now. The figures for slide film ranged between 5-6 and 7-8 stops, while negative film was consistently in the 10-11 stop range. I also came across this article, which looked at comparisons between digital and film, both theporetically and in practice. There are some flaws in the testing, as it involves scanning of the film images, which does increase noise and probably some other effects, but it does show that it isn't as clear cut as it is sometimes made out to be.

http://www.clarkvision.com/articles/dynamicrange2/
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Tijn

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Re: DR and RAW bit depth on Canon's forthcoming...
« Reply #19 on: February 26, 2012, 06:33:24 AM »
The human eye is a precision instrument, it will detect meaningful differences if they exist. If it can't detect them, then they are irrelevant, no matter what tests tell you. It's not much use having an extra stop of DR, if your meduim of choice can't show it. I suspect that you'd need an expensive Spectraview type monitor to see any differences.
See the above video and you'll understand why you're thinking too quickly. The human eye has MASSIVE dynamic range. We can see out of a window and still see every detail in the dark room we're in. When taking a photograph out of a window, the result is that the room will be severely underexposed. We need to push up its exposure in post-processing to recover any detail in the underexposed area. Just simply overexposing shadows will show you a difference in dynamic range, which by the way is a real-life-situation thing, as that's extremely common in postprocessing images. The fact that cameras lack this dynamic range is the whole reason why HDR photography exists.
Cameras are still very far from having the dynamic range or sensitivity of the human eye.

Flake

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Re: DR and RAW bit depth on Canon's forthcoming...
« Reply #20 on: February 26, 2012, 06:58:15 AM »
The human eye is a precision instrument, it will detect meaningful differences if they exist. If it can't detect them, then they are irrelevant, no matter what tests tell you. It's not much use having an extra stop of DR, if your meduim of choice can't show it. I suspect that you'd need an expensive Spectraview type monitor to see any differences.
See the above video and you'll understand why you're thinking too quickly. The human eye has MASSIVE dynamic range. We can see out of a window and still see every detail in the dark room we're in. When taking a photograph out of a window, the result is that the room will be severely underexposed. We need to push up its exposure in post-processing to recover any detail in the underexposed area. Just simply overexposing shadows will show you a difference in dynamic range, which by the way is a real-life-situation thing, as that's extremely common in postprocessing images. The fact that cameras lack this dynamic range is the whole reason why HDR photography exists.
Cameras are still very far from having the dynamic range or sensitivity of the human eye.

Except that the human eye does not work in the same way as a camera!  Persistence of vision means that we are able to scan a scene and the iris is able to adjust its aperture to allow less light to reach the retina, giving the impression that we have a huge dynamic range when we do not.  In addition rods and cones in the retina allow difference sensitivities to light, and we can to some extent see in very low light, albeit only in black & white.

The human eye has an approximate focal length of 50mm and around 50MP equivalent, having two of them on the front of the head means we have stereoscopic vision and can perceive depth and 3D, again without two images a camera cannot replicate this.

Tijn

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Re: DR and RAW bit depth on Canon's forthcoming...
« Reply #21 on: February 26, 2012, 07:16:06 AM »
Except that the human eye does not work in the same way as a camera!  Persistence of vision means that we are able to scan a scene and the iris is able to adjust its aperture to allow less light to reach the retina, giving the impression that we have a huge dynamic range when we do not.
I'm aware of that. And yet, we do have a very large "dynamic range" even when counting in that difference. We can see stars and we can see outside on sunny days, but not at the same time. Still, we can see outside a window and at the same time keep seeing detail of the room inside. Without pupil adjustments. My camera won't do that as well as I "do", at least not without post-processing.

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Re: DR and RAW bit depth on Canon's forthcoming...
« Reply #21 on: February 26, 2012, 07:16:06 AM »

tt

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Re: DR and RAW bit depth on Canon's forthcoming...
« Reply #22 on: February 26, 2012, 08:15:10 AM »
Except that the human eye does not work in the same way as a camera!  Persistence of vision means that we are able to scan a scene and the iris is able to adjust its aperture to allow less light to reach the retina, giving the impression that we have a huge dynamic range when we do not.
I'm aware of that. And yet, we do have a very large "dynamic range" even when counting in that difference. We can see stars and we can see outside on sunny days, but not at the same time. Still, we can see outside a window and at the same time keep seeing detail of the room inside. Without pupil adjustments. My camera won't do that as well as I "do", at least not without post-processing.

Out of curiosity - what would be the resolution of the foveal vision?

KeithR

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Re: DR and RAW bit depth on Canon's forthcoming...
« Reply #23 on: February 26, 2012, 08:38:07 AM »
As long as I can get from this:



to this:



And from this:



to this:



with my 7D, I don't see what the problem is - there's pretty wide DR in those.

Personally though, DR at the top of the histogram is what matters to me, and that seems to be Canon's priority too, I'm pleased to say:





(No idea why the "recovered" bike image is presenting small here, it's the same size as the underexposed one...)

And I suppose this post will get me some more negative karma from the children here...
« Last Edit: February 26, 2012, 08:44:07 AM by KeithR »

Marsu42

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Re: DR and RAW bit depth on Canon's forthcoming...
« Reply #24 on: February 26, 2012, 09:05:56 AM »
with my 7D, I don't see what the problem is - there's pretty wide DR in those. Personally though, DR at the top of the histogram is what matters to me, and that seems to be Canon's priority too, I'm pleased to say:

... but there's a catch: I used to use the htp mode on my 60D on every shot until I realized that even the expanded iso range compresses the shadows so much that recovering them brings in much noise. Nowadays, I simply underexpose 1/3ev and shoot raw - the only drawback that highlight recovery in lightroom torpedoes clarity when used at the same time.

However, I agree with you that the current 18MP sensor has enough headroom for most shots, and if not it's in typical hdr situations when a bit higher dr wouldn't be of any use anyway.

Mt Spokane Photography

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Re: DR and RAW bit depth on Canon's forthcoming...
« Reply #25 on: February 26, 2012, 12:01:26 PM »
As long as I can get from this:


The human eye can see much of the fine detail missing in the images, even after they are adjusted.  Things can always be better. 

thatcherk1

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Re: DR and RAW bit depth on Canon's forthcoming...
« Reply #26 on: February 26, 2012, 12:41:01 PM »
I think the main point of this thread isn't that we want to shoot the sunset without filters and expect perfect exposure from shadows to the sun itself.  I think what people are wanting is Canon to produce a sensor with DR that other manufacturers have already achieved.  It's more of a comparison to other brands and a worry that Canon will continue to fall behind with DR.  In a day and age of "raw" workflows, people like the idea that they can shoot in the field, and spend hours and hours perfecting a digital grad filter rather than be stuck with a poor decision made when taking the photograph.  Sometimes I'd prefer to just get it in the ballpark in the field, and not have to touch it much in post.  But I certainly can't fault anyone who wants to perfect it later.  With digital raw workflow we can achieve some beautiful (and realistic looking) images that would have been difficult or impossible in the days of film with only "in the field" and limited darkroom tools.

Also a note about monitors/photo paper, etc.  In practical terms, people want a couple more stops of DR not so they can get some muddy looking image that shows 14 stops of latitude.  The purpose is to smartly make adjustments in LR and PS to display those 14 stops in a beautiful way with things like the curve tool, or the grad/brush tools in LR.  Or for others such as photojournalists, occasional under/overexposure happens, and more photos will be recoverable if there is more DR to work with especially with LR4(beta)'s exposure adjustment which is highly accurate to actual in-camera exposure adjustment.

Adobe's latest raw processing is exceptionally good at rolling off highlights similar to the way film does.  It makes clipping sections of the image look much more pleasant.  As soon as I start pulling exposure in LR, that nice roll-off begins to lessen until the clipping looks like crappy old digital.  So any number of stops that are added to a camera's capability will only improve the beautiful film-like rolloff.

And as to a comment about how some images you want washed out, it's insanely easy to take even a 30 stop HDR and  crush it down to 1 stop of range.  It's never a problem to limit DR in post.

LetTheRightLensIn

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Re: DR and RAW bit depth on Canon's forthcoming...
« Reply #27 on: February 26, 2012, 12:44:52 PM »

Personally though, DR at the top of the histogram is what matters to me, and that seems to be Canon's priority too, I'm pleased to say:


Most DSLR sensors are linear capture so there is no such thing as "at the top of the histogram" and the fact is you can't get out of a 7D image (and yes I have one) wht you can from a D7000 at ISO100.

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Re: DR and RAW bit depth on Canon's forthcoming...
« Reply #27 on: February 26, 2012, 12:44:52 PM »

LetTheRightLensIn

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Re: DR and RAW bit depth on Canon's forthcoming...
« Reply #28 on: February 26, 2012, 12:50:46 PM »
I've said before, that lab tests are pretty meaningless, unless they reflect the real world, after all, as photographers, we are judged by what we achieve, not by what could be theoretically achieved.

But they do! Have you seen what a heavily pulled D7000/D3x ISO 100 shots looks like compared to one from 50D or 5D2?

Quote
Flake mentioned the use of HDR and grad filters. As a landscape photographer, I know that even with an extra stop of DR, there is no way that I could capture most scenes without using grad filters, unless I make some compromises. In fact, photography is all about making compromises, that is what sets the greats apart from the merely good.

But once you are into nearly 3 stops of usably better DR then it does start to make much more a difference in what things you can capture or not.

Quote
It's not much use having an extra stop of DR, if your meduim of choice can't show it. I suspect that you'd need an expensive Spectraview type monitor to see any differences.

Not at all. In fact most of them are IPS and don't even have very huge contrast ratio compared to some cheap SPVA screens. But it makes a big difference either way.

And seriously if Canon had 3 usable stops better DR like it did back when, compared to Nikon, would all of you still be finding every excuse in the world why we don't need it and who cares??

Why would anyone, most of all a Canon user, NOT want Canon to fix this up???
I care because I have Canon equipment.


LetTheRightLensIn

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Re: DR and RAW bit depth on Canon's forthcoming...
« Reply #29 on: February 26, 2012, 12:53:45 PM »
You don't need to do the Stoffer Wedge Test, its been done many times.  You can see the usable DR range of competiting camera bodies here:

5D MK II         8.4 EV
Nikon D700    7.8 EV

http://www.dpreview.com/reviews/CanonEOS5DMarkII/page25.asp

You can get more by manipulating RAW files, but the images tend to look flat and ugly.

I'd also like more DR, but, so far, no one seems to match film.

DPR test is ridiculous, it depends on nothing other than what tone curve is in the jpg setting.

You still get a tone curve processing in RAW.  you have to manulipate it to get a little more DR.  Then images tend to look flat.  DPR tells you the real world info.  Its like a statement of what you get off the showroom floor whan you buy a automobile, its what many, if not most get.

No you don't have to make it flat, you just apply special curves, maybe even different ones to different parts of the image and you can end up with rich contrast and color and nice detail without too much mush/noise/poor color and without weird over the top HDR look if you go about it right.

DPR doesn't come close to telling you the real world info. Even without using just a simple curve the in cam jpgs don't come close to the real story from RAW. You could easily chose a jpg style that would make any DSLR look better than any other from DR and then you coudl pick another one and reverse the results.

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Re: DR and RAW bit depth on Canon's forthcoming...
« Reply #29 on: February 26, 2012, 12:53:45 PM »