Raw + exposure compensation

taob · Post by **taob** » Sun Dec 21, 2003 1:09 am

What is everyone doing with raw images (Canon 10D in my case) that have exposure compensation applied to them? I used Capture One first in my workflow, then NeatImage for shots that need it, then finally Photoshop or GIMP.

I was thinking about this when trying to rescue some underexposed shots with a +2 or greater exposure comp in C1. Obviously, the noise characteristics of an ISO 100 shot without EC are different from the same ISO 100 shot with a +2 EC. My question is, does "ISO 100 +2EC" equal "ISO 400"? I recall several discussions in the past suggesting they are not quite the same. A properly exposed ISO 400 shot is preferable to an ISO 100 shot pushed two stops. I'm guessing "preferable" means "less noise".

So what I am doing now is creating a set of profiles specifically tuned for C1 users (no noise reduction, no sharpening) for ISO 400 to 3200, with 0, +1 and +2 EC at each ISO. This is a total of 12 profiles. If this works better than using, say, an ISO 3200 profile for an ISO 800 image pushed two stops, then I'll also try it with ISO 100 and 200, and -1 and -2 EC.

taob · Post by **taob** » Mon Dec 29, 2003 7:17 am

I can see now that an image shot at ISO 400 and then pushed 2 stops has a different noise profile than the same image shot at ISO 1600 in the first place. The profile created from an ISO 400 + 2EV test image is different from an ISO 1600 one, according to the displayed numbers in NI.

The twelve profiles can be downloaded here:
http://www.risc.org/canon10d-c1rawjpg.zip (44K)

One of the test images used to build a profile is here:
http://www.risc.org/iso0400+0-c1.jpg (2424K)

I can also supply full profiles (with the image preview) and all original CRW files, if anyone is interested.

Comments are welcome.