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Author Topic: How much DR do we need?  (Read 4124 times)
ErikKaffehr
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« on: April 02, 2013, 03:38:32 PM »
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Hi,

I analyzed a lot of images with RawDigger recently and found very few images fully utlizing the DR my cameras. Here are some examples:

This is a typical landscape image with about 8EV DR. The image is not exposed to the right, probably due to some specular reflections being taken into account when checking blinking highlights.

The raw histogram:

The full mage is here: http://echophoto.dnsalias.net/ekr/Articles/HowMuchDR/Lighthouse.jpg
Here is the DNG files: http://echophoto.dnsalias.net/ekr/Articles/HowMuchDR/Lighthouse.dng

This image taken at dawn has a wider dynamic range, at least 11 stops.


The full image is here: http://echophoto.dnsalias.net/ekr/Articles/HowMuchDR/Dawn.jpg
The DNG file is here: http://echophoto.dnsalias.net/ekr/Articles/HowMuchDR/Dawn_RD.png
There is still some noisy detail in the foreground tree:


Finally, if we include the sun we can have infinite dynamic range, except setting sun, it will always be clipped.


The full image is here: ]http://echophoto.dnsalias.net/ekr/Articles/HowMuchDR/WinterSun.jpg
The DNG file is here: http://echophoto.dnsalias.net/ekr/Articles/HowMuchDR/WinterSun.dng

Here is a shadow detail crop:


So here were some Sony Exmor sensors (Sony Alpha 99 and Sony Alpha 77). Would be great if Nikon, Canon and MF shooters also posted some high DR image samples.

Hints for evaluation:

I use log scale on Y-axis and EV scale on X-axis. I also use a cut of around 5k pixels/bin, so I count DR from maximum exposure to the position where histogram goes below 5K. This is almost arbitrary choice.

MFD will produce a different histogram, as they have 16 bit readout but around 3-4 bits of noise. So the histogram will not roll off but continue to the left edge. But channels below 5K will probably be just noise.

Best regards
Erik




« Last Edit: April 02, 2013, 10:52:01 PM by ErikKaffehr » Logged

IanBrowne
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« Reply #1 on: April 07, 2013, 11:46:49 PM »
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interesting; 200+++ hits and no reply  Wink

Personally Erik, I don't go into too much pixel peeping stuff. We can get bogged down by worrying about too many of the finer details of digital photography. I don't think I have ever thought about DR of any my digital cameras and in film days I didn't worry too much about this colour channel of that film and that colour channel of this film. I'm not that good of a photographer to notice the difference  Cry

So I guess I cannot help you. I just take photos using RAW format so I can fix my bad photography  Embarrassed on the computer. Apart from cropping I cant fix composition so that's what I worry about the most.  Smiley
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bill t.
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« Reply #2 on: April 08, 2013, 12:12:28 AM »
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Nice pictures Erik!

I think we've conditioned ourselves to avert our eyes from pictures that need lots of dynamic range.

Here are a couple of daring Coolpix A shots that really do make use of a heck of a lot of dynamic range, and to good effect.  Even these lowly jpg's can reveal a lot of useful detail in the inky shadows in PS or LR.

Look at the "original" sized DSC_0045 and DSC_0049 here...

http://www.dpreview.com/galleries/reviewsamples/albums/nikon-coolpix-a-preview-samples

You can push 'em pretty hard.  DSC_0128 has a certain tonal something, as well.

I'm happy to have all the dynamic range I can get.  I just love lots of glowering shadow detail combined with sparkly highlights and it's it comforting to know I can re-think an entire image long after I shoot it.  And I'm sick to death of HDR.  D800, yeah baby!

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Rob C
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« Reply #3 on: April 08, 2013, 02:37:59 AM »
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interesting; 200+++ hits and no reply  Wink




It's simply too removed from the art of photography. Were one interested in the why/how of digital camera workings, then yes, I suppose it means something, but it is anything but essential to the art of snapping a fine snap: that you do by instinct and, with digi, the easy peep at the rear screen. I had little idea of how Kodachrome was made and even less of its processing - it made no difference at all to my ability to use the film. It's just a subject about something quite else than pictures. Nothing wrong with that at all, just probably why not many people are interested enough to write.

IMO.

Rob C
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HarperPhotos
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« Reply #4 on: April 08, 2013, 02:49:54 AM »
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Hello,

This reminds me back in the mid 70s my brother and I where getting into hifi equipment. We even tried different stylist and would listen to the same song on the record to listen to the differences the stylist would reproduce the sound.

After some months I came to the resolution I wasnt actually listening to the song for what is was but listing to the sound it made. That was the end of my foray into the world of hifi.

Do ya get what Im saying.

Cheers

Simon
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Simon Harper
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Petrus
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« Reply #5 on: April 08, 2013, 02:50:27 AM »
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We need infinite DR, then cameras would not need exposure meters and all exposing could be done just for the required DOF and shutter speed.

In the audio side there already are analog to digital converters with 26 bit (stop in photo language) resolution, which require no level setting with mic preamplifiers.
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hjulenissen
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« Reply #6 on: April 08, 2013, 03:02:47 AM »
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In the audio side there already are analog to digital converters with 26 bit (stop in photo language) resolution, which require no level setting with mic preamplifiers.
I have never heard of more than 20-21 effective bits. Do you have any references?

-h
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hjulenissen
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« Reply #7 on: April 08, 2013, 03:06:34 AM »
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High DR sensors does have merits for shooting low-DR scenes without having to set exposure, and for "ISO-less" shooting where you set time/aperture from artistic vision and to avoid clipping but do not touch ISO.

For for capturing a single high-DR scene, you probably don't need much more sensor DR than the lense DR. So what is the lense DR? Can it be measured/analyzed in any sensible, repeatable fashion? Is the lense DR any different for a dark scene with a single, bright spot (moon/sun/...) than if the "brightness" is distributed over a larger area?

-h
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Petrus
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« Reply #8 on: April 08, 2013, 06:59:17 AM »
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I have never heard of more than 20-21 effective bits. Do you have any references?

Stagetec Truematch standalone converter, 28 bit conversion with 26.5 bit resolution.

http://www.stagetec.com/en/audio-technology-products/standalone-converter.html

If the end result is any better than using conventional 24 bit converters and adjustable gain mic-pres is another matter, though. I am happy with my Prism Orpheus and Sound Devices 722, they both give about 21 bit resolution. Recording venues limit the achievable clean resolution to around 12-14 bits anyway (ambient noise), unless the aim is to accurately record the air conditioning and traffic, also.
« Last Edit: April 08, 2013, 07:03:24 AM by Petrus » Logged
ErikKaffehr
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« Reply #9 on: April 08, 2013, 07:27:23 AM »
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Hi,

We have only around 60 thousands of electrons per pixel, and we can not read out with less then 1 electron precision so we would do fine with 16 bits.

BR
Erik

Stagetec Truematch standalone converter, 28 bit conversion with 26.5 bit resolution.

http://www.stagetec.com/en/audio-technology-products/standalone-converter.html

If the end result is any better than using conventional 24 bit converters and adjustable gain mic-pres is another matter, though. I am happy with my Prism Orpheus and Sound Devices 722, they both give about 21 bit resolution. Recording venues limit the achievable clean resolution to around 12-14 bits anyway (ambient noise), unless the aim is to accurately record the air conditioning and traffic, also.
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PeterAit
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« Reply #10 on: April 08, 2013, 08:01:31 AM »
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It's simply too removed from the art of photography. Were one interested in the why/how of digital camera workings, then yes, I suppose it means something, but it is anything but essential to the art of snapping a fine snap: that you do by instinct and, with digi, the easy peep at the rear screen. I had little idea of how Kodachrome was made and even less of its processing - it made no difference at all to my ability to use the film. It's just a subject about something quite else than pictures. Nothing wrong with that at all, just probably why not many people are interested enough to write.

IMO.

Rob C

I agree. It makes me think of a painter spending lots of time doing chemical analyses on his paints and brushes. Nothing whatsoever to do with the art.
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Peter
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Slobodan Blagojevic
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« Reply #11 on: April 08, 2013, 09:14:12 AM »
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... It makes me think of a painter spending lots of time doing chemical analyses on his paints and brushes...

Oh, but they did.
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fredjeang2
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« Reply #12 on: April 08, 2013, 11:25:13 AM »
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Oh, but they did.

Present me those painters !  Wink Most of the big bosses I have been working in still with hardly know their camera menus and rely
on assistants for that.

In fact, those graphics and science or pseudo-science were irritating me in the past. Now I have a different view on them.
It is simply due to the fact that there isn't one photographer's profile as ideal but many.

There are people who come from an engineering or technician background, that don't necesarly have to leave with photography
and there are more interested on the engineering side.
For them, graphics talk to them, 1 point DR talk to them, the life of the photons talk to them more than the life of the model.
It's chinese lenguaje for me but for others it's a of great interest.

Photography, as a form of art that is created from complex engineered machines,
will always attract people with clear tech orientation because it has this component inside. And their views and interests are as valid as others.

« Last Edit: April 08, 2013, 11:34:55 AM by fredjeang2 » Logged
ErikKaffehr
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« Reply #13 on: April 08, 2013, 11:56:41 AM »
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Hi,

The reason I posted my observations was mostly that I feel DR is overemphasized. I have very seldom encountered subjects with very wide DR. So what I wanted was to check the DR of different subjects and also point a bit towards Rawdigger to check out raw files. In principle, I think it is good to know your tools.

Raw converters can do a lot of tricks. For instance, Rawdigger can present an accurate histogram from raw, neither Lightroom or in camera histograms are really accurate. In camera histograms are said to be based on a JPEG interpretation of the image and Lightroom does highlight recovery behind the scenes.

This posting was posted on the "Cameras, Lenses and Shooting gear" forum, so I think it's quite OK to start a discussion like this.

Best regards
Erik
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Slobodan Blagojevic
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« Reply #14 on: April 08, 2013, 11:57:45 AM »
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Present me those painters !...

Almost all classic painters, from Leonardo onward (and probably even before him), were very particular about the quality and longevity of their paints. They were known to experiment, mix and match, trying to find a perfect formula. Looks like most of them succeeded, although some artwork faded faster than others.
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Slobodan

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« Reply #15 on: April 08, 2013, 12:10:01 PM »
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The reason I posted my observations...

Hi Erik,

To tell you the truth, I am still struggling to understand the reason behind this thread. Are you suggesting that, in real life, scenes do not have more than 11 stops? In which case the 3-stop advantage of D800 over 5DIII would not matter? You showed one such example, but then you said "There is still some noisy detail" in the shadows. Well, if it is noisy, than additional DR would have help, no?
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Slobodan

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fredjeang2
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« Reply #16 on: April 08, 2013, 12:19:35 PM »
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Almost all classic painters, from Leonardo onward (and probably even before him), were very particular about the quality and longevity of their paints. They were known to experiment, mix and match, trying to find a perfect formula. Looks like most of them succeeded, although some artwork faded faster than others.
Angry
No fun.
I thought you would have sent me the phone number of some lady painters in high-heels in Chicago district in search of the technical remedy to longevity. Booo.
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ErikKaffehr
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« Reply #17 on: April 08, 2013, 12:42:36 PM »
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Hi Slobodan,

It started that I bought a new camera and I was interested in seeing the purported advantage in DR. I knew the advantage was there but I could not find any subject showing it. Also, have seen very few images where I felt camera DR was a problem. So I started to check out many images and found that very few of my images had a dynamic range exceeding nine stops.

Also, the cameras I have used since 2006 had quiet decent DR, but also images from other cameras I have seen seldom had issues with DR. Another issue is that a very wide dynamic range needs a lot of tone mapping to be pleasant on screen.

Take this example from Gotland, Sweden, in this case I used HDR tone mapping and some other things on a single image;


Now, a straight import of the same image in Lightroom looks like this:



I don't think the second image is very attractive, but I'll admit that the first one is "over the top".

If I check out the DR in Rawdigger we can see that the dynamic range is around 8-9EV.
This is possibly even more obvious if I use a linear scale on the vertical axis of the histogram, see below.



So you need no DR champ to handle it, just learn to expose to the right and how to process your images and chances are you can be happy with the gear you have!

Best regards
Erik

Hi Erik,

To tell you the truth, I am still struggling to understand the reason behind this thread. Are you suggesting that, in real life, scenes do not have more than 11 stops? In which case the 3-stop advantage of D800 over 5DIII would not matter? You showed one such example, but then you said "There is still some noisy detail" in the shadows. Well, if it is noisy, than additional DR would have help, no?
« Last Edit: April 08, 2013, 12:50:06 PM by ErikKaffehr » Logged

Slobodan Blagojevic
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« Reply #18 on: April 08, 2013, 12:57:17 PM »
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Erik,

In the OP, you presented one image with "at least 11-stop DR." That's approximately 5DIII range. Now, if someone shot the same scene with a D800, using the same parameters, the resulting initial image would be the same. However, the ability to pull cleaner details from that tree in the foreground should be different.

Thus, if the scene has 11-stops in itself, and we do not want to change the apparent tonal relationships within it (like in your example, where leaving things in the shade as near silhouettes works well visually) , than an 11-stop DR camera would suffice. If, however, we do need/want to pull out details in the shade, than a higher DR camera would be preferred, right?

I know that, as a good friend, you are just trying to dissuade me from the financial disaster that switching to Nikon would be for me, but your examples are not helping Grin
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Slobodan

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ErikKaffehr
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« Reply #19 on: April 08, 2013, 01:09:20 PM »
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Slobodan,

You are actually right on all three issues ;-)

Just so you know: My best friend also owns Canon, had 20D and 40D and has just recently upgraded to 5DIII. I never felt that his tools were lacking.

Best regards
Erik




I know that, as a good friend, you are just trying to dissuade me from the financial disaster that switching to Nikon would be for me, but your examples are not helping Grin
« Last Edit: April 08, 2013, 01:31:55 PM by ErikKaffehr » Logged

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