7D dynamic range?

[nikrphoto]

Color neg film has typically a 9 stop range. How about the latest digi sensors like the 7D's? Is there any measure of how much of a range they are able to record. Portrait photographers are very critical of the exposure with digital cameras as they can very easily over/under expose their subjects.

 

[Keith Reeder]

Something approaching 12 stops for the 7D - although this changes quite significantly depending on ISO.

 

[nikrphoto]

so is it 12 stops at iso100?(or its equivalent). If thats so, its more than color neg film.

 

[PicPocket]

so is it 12 stops at iso100?(or its equivalent). If thats so, its more than color neg film.

7D is still to show up in reviews, but if we take an example, 40D was 9.1EV at ISO100 in DPR review: http://www.dpreview.com/reviews/canoneos40d/page20.asp

From what we have heard, 7D should improve this further

As far as film, it also depended on film type. Not all film was 9 stop capable

--
PicPocket
http://photography.ashish-pragya.com

 

[tigger183234]

I also was pretty surprised when I heard that digital cameras have 9 stops of DR, as I learned negativ film has 7-9 stops DR.

Unfortunatly I can't find the website right now, but I once saw a comparison on a website that showed that film is more like 14 stops DR.

Maybe the lower number we still know for film are centuries old.
Film still has a higher dynamic range when digital cameras.

 

[RedFox88]

I also was pretty surprised when I heard that digital cameras have 9 stops of DR, as I learned negativ film has 7-9 stops DR.

Unfortunatly I can't find the website right now, but I once saw a comparison on a website that showed that film is more like 14 stops DR.

Here's a pretty good test:
http://forums.dpreview.com/forums/read.asp?forum=1031&message=32891438

One thing in DPR's review, they list a maximum/best DR for a dSLR that is often 11 to 12EV. Yet often state, not in every review and not sure why not, that their "best" DR image would not look good since it would be a concave tone curve very low in contrast instead of the typical "S" tone curve.

 

[HotspurJr]

Dxomark does DR tests of raw image files, which is often better than what DPR does, which is looking at the default tone curves assigned.

Looking at the post-tone-curve JPG is probably a better comparison to film (where you tone curve is largely determined by your choice of film), and, not surprisingly you see about 9 stops, which digital doing a little better in shadows, and film doing a little better in highlights.

However, if you look at the raw files, you'll see that at ISO 100 both teh 50D and the 5D2 (there are no tests yet on the 7d) get around 11 stops. The 7D will probably be closer to the 50D, so it's worth looking a bit deeper:

at ISO800 the 50D has 10 stops, but as ISO increases after that DR decreases almost stop-for-stop. (eg 9 stops at 1600, 8 stops at 3200, etc). The 5D2 avoids this steep decline for another stop, but from 1600 on up you see a similar thing: losing almost a stop of DR for every increased stop of ISO.

(I'd give you a link, but DXO's links don't paste very well. Go do DXOmark.com and compare a 50d to a 5D2, then select the DR chart).

It is not surprising, when you look at these charges, that above 800 is where noise starts to be an issue on the 50D, and above 1600 is where it starts to be one on the 5D2.

 

[rhlpetrus]

I also was pretty surprised when I heard that digital cameras have 9 stops of DR, as I learned negativ film has 7-9 stops DR.

Unfortunatly I can't find the website right now, but I once saw a comparison on a website that showed that film is more like 14 stops DR.

Here's a pretty good test:
http://forums.dpreview.com/forums/read.asp?forum=1031&message=32891438

One thing in DPR's review, they list a maximum/best DR for a dSLR that is often 11 to 12EV. Yet often state, not in every review and not sure why not, that their "best" DR image would not look good since it would be a concave tone curve very low in contrast instead of the typical "S" tone curve.

RAW DR has been tested at most at 13stops (MF backs). The tone curves used by in-camera processing are usually steep and don't show that.

The "ACR best" from DPR is not really the best one can get, since it's just some sort of settings from ACR sliders. One can develop his own tone curve with more careful work for conversions and get closer to RAW DR, loosing no midtone contrast (steepness of central part of curve) but gently rolling off HLs and slowly getting to LLs.
--
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Good shooting and good luck
(after Ed Murrow)

 

[Julio]

Most Canon bodies--and from what I have seen posted from some preliminary tests here the 7D is no exception have slightly better DR @ 200 than 100 and then it gradually gets worse as you increase the ISO.

 

[The Davinator]

...is around 9 to 10 stops. This is close enough to the 12 stop max I get with well scanned and processed color neg film to not cause any problems.....and way better than the 6 or so stops from E6 films I use for landscape work. If you can work with positive films, then any DSLR now is a snap to use.

 

[GaborSch]

Most Canon bodies--and from what I have seen posted from some preliminary tests here the 7D is no exception have slightly better DR @ 200 than 100 and then it gradually gets worse as you increase the ISO

I don't know of any modern Canon DSLR which would have greater DR with ISO 200 than with ISO 100. Just the opposite: the DR is always greater with ISO 100, althiugh the difference is tiny in some cases.

--
Gabor

http://www.panopeeper.com/panorama/pano.htm

 

[GaborSch]

The dynamic range of a digital camera depends on one's acceptance of the noise. In turn, the acceptance often depends on the setting: one is accepting more noise in a very low-light setting, like a night stage shot than in a daylight landscape.

Thus it is not reasonable to talk about a specific number as if the DR would be something universal measurement.

Add to this, that the appearance of the noise too is a factor; think of the 5D2's pattern noise.

--
Gabor

http://www.panopeeper.com/panorama/pano.htm

 

[John Sheehy]

Most Canon bodies--and from what I have seen posted from some preliminary tests here the 7D is no exception have slightly better DR @ 200 than 100 and then it gradually gets worse as you increase the ISO.

Again, that is only true of specific bodies. The 20D did not have enough highlight headroom for the RAW values to go as high at ISO 100 as they did at ISO 200, and read noise was roughly the same.

This is not a general characteristic of Canon digitals. Most of them have as much highlight headroom at ISO 100 as at ISO 200.

--
John

 

[John Sheehy]

Something approaching 12 stops for the 7D - although this changes quite significantly depending on ISO.

By the engineering definition, of max signal divided by noise floor, the 7D should give about 1/4 stop more pixel DR than the 50D at base ISO, and 3/4 stop more at high ISOs. At the image level, a tad more.

That's based on simple standard deviation noise statistics, however, which do not account for pattern noise, and the 7D seems to have less of that at both ends of the ISO spectrum, so practical DR may be a little better than I said.

--
John

 

[WalterSobchak]

Is that really 12 usable stops that you can get info from, or just some measure a reviewer threw out?

Are you getting 9 stops for b&w neg from specs or from scans and tests?

 

[Julio]

Again, that is only true of specific bodies. The 20D did not have enough highlight headroom for the RAW values to go as high at ISO 100 as they did at ISO 200, and read noise was roughly the same.

It was back in the 20D days when I got in the habit of shooting @ 200... I could have sworn there was a graph posted here by someone in the last couple of weeks that showed a slight bump up in DR for several Canon bodies @ 200, including the 7D but I can't seem to find the thread atm... I'll look for it.

Edit: found it... seems ISO200 has either the same or slightly better DR in those measurements... what do you think?

http://forums.dpreview.com/forums/read.asp?forum=1019&message=33018892

 

[GaborSch]

Edit: found it... seems ISO200 has either the same or slightly better DR in those measurements... what do you think?

There is nothing like that there. ISO 100 is better than 200 with all present Canons, which is pretty natural.

--
Gabor

http://www.panopeeper.com/panorama/pano.htm

 

[caterpillar]

The dynamic range of a digital camera depends on one's acceptance of the noise. In turn, the acceptance often depends on the setting: one is accepting more noise in a very low-light setting, like a night stage shot than in a daylight landscape.

Thus it is not reasonable to talk about a specific number as if the DR would be something universal measurement.

Add to this, that the appearance of the noise too is a factor; think of the 5D2's pattern noise.

Noise and Dynamic Range (DR) are two different issues. It is commonly acknowledged that film negatives have about 12-13 EV vs digital at around 9-9.8 give or take, as far as DR is concerned. If your argument is correct, then it would be best for me to use a digicam to shoot wide EV subjects because most sensors have clean ISO 800. That same ISO 800 would be very grainy with film. Even today's ISO 400 film is grainy. Now does that mean film has less DR?

DR, for me, is the range of values where a media is able to render the dark and light areas in an image. A medium with a good DR renders these light and dark areas in such as way as to preserve the detail and render the transition from one EV to the next smoothly or "gracefully," so that the eyes do not see a harsh boundary where the transition from one EV to the next happened. A good medium also allows for a wider range of values so that it allows for brighter and the darker scenes to be "seen" and captured but still retain detail. The image captured can have noise, but if it can "see" those details in and render them "gracefully" from one value to the other, then one can say that the medium has a good DR.

In all these, noise is not the issue.

--
--------------------

• Caterpillar

'Always in the process of changing, growing, and transforming.'

 

[Gao Gao]

DR is a function of noise, and more.

Grains in film is different from noise in digital in that it's a pattern noise intrinsic to the film, whose appearance is not affected by exposure. In digital (or rather electronic, be it analogue or digital), higher signal means less visible noise. Below certain SNR level, the details are corrupted by noise beyond recognition.

The dynamic range of a digital camera depends on one's acceptance of the noise. In turn, the acceptance often depends on the setting: one is accepting more noise in a very low-light setting, like a night stage shot than in a daylight landscape.

Thus it is not reasonable to talk about a specific number as if the DR would be something universal measurement.

Add to this, that the appearance of the noise too is a factor; think of the 5D2's pattern noise.

Noise and Dynamic Range (DR) are two different issues. It is commonly acknowledged that film negatives have about 12-13 EV vs digital at around 9-9.8 give or take, as far as DR is concerned. If your argument is correct, then it would be best for me to use a digicam to shoot wide EV subjects because most sensors have clean ISO 800. That same ISO 800 would be very grainy with film. Even today's ISO 400 film is grainy. Now does that mean film has less DR?

DR, for me, is the range of values where a media is able to render the dark and light areas in an image. A medium with a good DR renders these light and dark areas in such as way as to preserve the detail and render the transition from one EV to the next smoothly or "gracefully," so that the eyes do not see a harsh boundary where the transition from one EV to the next happened. A good medium also allows for a wider range of values so that it allows for brighter and the darker scenes to be "seen" and captured but still retain detail. The image captured can have noise, but if it can "see" those details in and render them "gracefully" from one value to the other, then one can say that the medium has a good DR.

In all these, noise is not the issue.

--
--------------------

• Caterpillar

'Always in the process of changing, growing, and transforming.'

--

. 。o O o 。 . 。o O o 。 . 。o O o 。 .

 

[pdqgp]

Noise and Dynamic Range (DR) are two different issues.

In all these, noise is not the issue.

DR and Noise are not two different issues. Just as within the world of Audio, Signal to Noise ratios absolutely come into play when measuring dynamic range.

I could go on, but I think the following artical outlines it best. Doug is on the forum and I'm sure will chime in on the matter.

http://doug.kerr.home.att.net/pumpkin/ISO_Dynamic_range.pdf

Again, not sure if you're an audiophile, but do some googling and you'll be able to see it matters in that world too.

--
-tim

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