Balancing Exposure and Processing

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Blade Canyon

Senior Member
Felisek said:
I understand very well what you are saying, but please consider this.
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I was a non-believer, too, until I did some experiments that basically proved J-see is right. It didn't matter if I was shooting indoors or long exposure night shots, so long as the exposure time and aperture were the same: a RAW file shot at 100, boosted 4 stops in ACR, looked exactly the same as a RAW file shot at ISO 1600. They were indistinguishable from any standpoint, including noise or artifacts.

Now, I have not seen any evidence in my tests that shooting at 100 gave me a BETTER shot, but the evidence is clear that a low ISO is definitely better than an ISO too high, because even just a little "overexposure" (too high ISO) caused data loss (blow outs) in the higher ISO file, while the lower ISO shots kept the data.

I have the shots on my home PC that can prove this, but am at work now. Can post them later.

Does this mean I'm going to set my D800 on ISO 100 all the time? No, because I often like to have properly exposed JPEGs SOOC that don't require any post processing, and I like to see and evaluate my work on the back of the camera while shooting.

There is an exception that I haven't tested, and that's whether the camera's high-ISO noise reduction creates a cleaner shot, because this camera feature would not kick in shooting as ISO 100.
 
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J

J-see

Senior Member
Blade Canyon said:
I was a non-believer, too, until I did some experiments that basically proved J-see is right. It didn't matter if I was shooting indoors or long exposure night shots, so long as the exposure time and aperture were the same: a RAW file shot at 100, boosted 4 stops in ACR, looked exactly the same as a RAW file shot at ISO 1600. They were indistinguishable from any standpoint, including noise or artifacts.

Now, I have not seen any evidence in my tests that shooting at 100 gave me a BETTER shot, but the evidence is clear that a low ISO is definitely better than an ISO too high, because even just a little "overexposure" (too high ISO) caused data loss (blow outs) in the higher ISO file, while the lower ISO shots kept the data.

I have the shots on my home PC that can prove this, but am at work now. Can post them later.

Does this mean I'm going to set my D800 on ISO 100 all the time? No, because I often like to have properly exposed JPEGs SOOC that don't require any post processing.
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I've been shooting the two methods before and when I processed them, I'll see where they differ or at what point they start to differ enough.
 
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J-see

Senior Member
These are two. Mind you, it's very hard to take identical shots of moving subjects. I'll try again when I have the short lens with me and do landscapes although there ISO isn't needed in practice.

I selected two shots that both had the focus indicator in NX in the same location. Since the incoming signal isn't different, they both start to fall apart when zooming in. I set the white and black of both just before their clipping points and set WB identical. The rest of the processing is the same except the exposure adjustment for the 100. That I had to increase with 4 2/3th stop.

_DSC2748.jpg

_DSC2755.jpg

_DSC2748-2.jpg

_DSC2755-2.jpg

There might be a slight difference in focus but both were 'in focus' according the cam. I'll know more when the rest is processed. Focus isn't the main concern now; it is colors, brightness and shadows.
 
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Blade Canyon

Senior Member
Horoscope Fish said:
Noise, Dynamic Range and Bit Depth in Digital SLRs

Caveat: I didn't read the whole thing and, assuming I could manage to stay awake through long enough to do so, probably wouldn't understand 95% of it. Still, it looked relevant and I know some people loooove to geek out on this sort of thing, so yeah; go nuts. I'm out the door to go shoot a little.

....
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Thank you for posting that. The relevant part for this discussion is the "S/N and Exposure Decisions" segment. It was very interesting, but this is the conclusion:

"Bottom line: Read noise at high ISO is much smaller than read noise at low ISO, in terms of the error in photon counting that it represents. Thus, better image quality is obtained for using the highest ISO for which the signal is not clipped."

Which means I'll just go back to shooting like I've been shooting. Expose to the Right, even including the ISO setting.

I should clarify, however, that the author of that piece says "Exposing To The Right" by adjusting ISO is usually taught for the wrong reason, and that the usual arguments about levels and dynamic range are wrong (per J-see), but that the signal/noise ratio is the real reason to do it. If you read that segment, he's saying J-see is correct, right up until he explains the noise part.
 
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J

J-see

Senior Member
Blade Canyon said:
It appears 3200 was too much "gain" for the conditions on that shot.
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I used manual mode with auto-ISO so it picked what it needed with my fixed A and S settings. The others, I just disabled auto-ISO.

Here are some more. The difference in DoF might be distracting but it's the shadow and highlights where the difference should grow larger and larger. The higher the ISO, the more. The lower the ISO, the more they resemble each other.

_DSC2731.jpg
_DSC2732.jpg
_DSC2733.jpg
_DSC2738.jpg
_DSC2739.jpg
_DSC2740.jpg
 
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J-see

Senior Member
It's close to impossible to seriously test this with all the difference between RAW editors. Here's the exact same file. One with 2 stops of exposure more in NX, saved as a TiFF and processed in LR. One processed full and identical in LR.

_DSC2749.jpg

_DSC2749-2.jpg
 
J

J-see

Senior Member
I processed two of my 100 shots, one mostly in NX and the other in LR. I sharpened and fine-tuned both identical and then cropped to detail. There's too much difference between RAW editors to know if post-exposure will be better in post or done in cam.

You'll only find out when doing test shots and compare them. For me, at lower ISO the difference is small, as expected but at high ISO post-exposure wins.

Here's the two shots and a detail crop. It's unbelievable how they can differ. I even gave up trying to get them identical and processed the second to my liking.

_DSC2664.jpg

_DSC2664-3.jpg

_DSC2664-2.jpg

_DSC2664-4.jpg

LR is the "blue" one.

I know what brings best quality for me. You do what you like.
 
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Blade Canyon

Senior Member
J-see said:
There's too much difference between RAW editors to know if post-exposure will be better in post or done in cam. ...
I know what brings best quality for me. You do what you like.
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That's a good point. I've always used Adobe and considered it to be the gold standard.
 
J

J-see

Senior Member
Blade Canyon said:
That's a good point. I've always used Adobe and considered it to be the gold standard.
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The difference what I see in those two shots convince me even more to stick with Adobe. Either LR or PS. It's not necessarily the colors and such since those can always be adjusted but look at the eye, the scales and beak. It's not simply the colors that differ.

I always used NX as a viewer since I very quickly can maximize the shot compared to LR where I convert all to DNG. I'm not going to use it for anything else.
 
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Blacktop

Senior Member
I did some experimenting myself

100% crops.
1st shot is ISO 3200/ f/3.5 /shutter 1/15th

2nd shot. ISO 100 + 5EV in LR/ f/3.5/ shutter1/15th

Did not touch anything else. WB was set to auto in cam.

ISO3200--5272.jpg


ISO100+5ev-5273.jpg
 
B

Blacktop

Senior Member
I'm seeing some weird artifacts at ISO100 +5EV
Properly exposed at 3200 ISO there is noise, but more tolerable than the artifacts.

At 100% crop they both look pretty bad, but with no crop the 3200 ISO shot looks way better. IMHO
 
J

J-see

Senior Member
Blacktop said:
I'm seeing some weird artifacts at ISO100 +5EV
Properly exposed at 3200 ISO there is noise, but more tolerable than the artifacts.

At 100% crop they both look pretty bad, but with no crop the 3200 ISO shot looks way better. IMHO
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When I normalize exposure I don't pay attention to what ISO would have been used but just expose until it about looks right. Even when ISO would be, let's say, four stops more exposure, that's not necessarily what the 100 shot needs. The higher the ISO, the further apart. WB starts to change too and colors differ since the bits of high ISO go down the drain.
 
B

Blade Canyon

Senior Member
Blacktop said:
I did some experimenting myself

100% crops.
1st shot is ISO 3200/ f/3.5 /shutter 1/15th

2nd shot. ISO 100 + 5EV in LR/ f/3.5/ shutter1/15th

Did not touch anything else. WB was set to auto in cam.
Click to expand...

What happens if you go back to your RAW processor and set WB to the same value? Once I did that, or shot the scene with a fixed WB, the pics became similar. Your camera may have also added high ISO noise reduction to the one high ISO shot, but not the other, which is an argument for shooting at the higher end.
 
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