High ISO or Push The RAW File? (ACR/LR has a problem here!!)

Question

This topic has been discussed numerous times.
Should you shoot with high ISO or can you just push the exposure in your RAW converter?
What looks better?
What has more noise?
I tested. Nikon D300, shot inside, crappy tungsten light. Each scene I shot with a higher ISO and with the same aperture and shutter speed one stop lower ISO.
For instance:
- f/4, 1/80s, ISO800
- f/4, 1/80s, ISO1600
Now I went in ACR 5.2 and pushed the lower ISO shot 1 stop. Noise Reduction all off.
Here are the results:
- In ACR pushing 1 stop isn't enough. You need to push somewhat around 1.3 stops
- The color shifts in the pushed shot - more saturation, more contrast. Wood for instance gets significantly redder.
- Noise stays virtually the same!
Hmmm. So what would Nikon Capture NX 2 do? Again, NR all off.
That's what happens:
- Pushing 1 stop is enough. It does exactly what you'd expect.
- Color stays exactly the same.
- Noise stays exactly the same.
The shots are virtually indistinguishable!!
So what about 2 stops?!
The exact same results. The "problem" in ACR magnifies, you need to push around 2.6 to get there and saturation and contrast shift significantly now, to an extent where clipping and blocking happens.
Capture NX on the other hand again works flawlessly. No difference between ISO 1600 and ISO 400 pushed 2 stops. Noise? The same. Shadows? The same. Colors? The same.
Shadows don't get lost any more in an underexposed shot that's pushed 2 stops than they are in a shot with ISO two stops higher!
Very interesting. So with NX you could probably shoot the whole evening on ISO 200 and then push it later. Unfortunately NX can only go +2 stops ...
Last comment here:
Adobe need to do some homework here. A lot that is. The non linear increase of exposure, the shift in color and saturation and also the severe, blocky color noise that ACR/LR show in very high ISO shots are way below what we can expect.
Do you trust me or do I need to post the shots?
Cheers!
Thomas

Answer 1

Jeff Schewe says:
"Of course I don't trust you ..."
Sorry, it took me a while, but here are the shots. Initially I did a more sloppy handheld test but I wanted to do it right and now used a tripod and cropped exactly.
http://www.gg-images.us/misc/isovsev
The image names show the ISO, if it says -1 or -2 it means it was 1 or 2 stops underexposed and then pushed accordingly in the RAW converters.
The RAW files are at http://www.gg-images.us/misc/isovsev/raw
Lee Jay says:
"The "exposure" slider in LR/Camera Raw isn't a pure raw*2^exposure, and this is quite intentional."
And why is this so? And what is the intention?
Gordon McKinney says:
"And remember, the camera does an electronic amplification "push" of exposure on the sensor. It should perform better than software since it provide the A/D converts more signal to work with. ..."
The results from Capture NX look as if the software is doing just as good as the in-camera "push" that high ISO does.
Thomas