Originally Posted by andnowimbroke
You're not missing anything, Greg -- you've got it right.
The people who say "increase exposure compensation to get less noise at high ISO" are really just saying "use a lower ISO to get less noise", though most of them don't realize it.
If you take an "ISO 100" raw file that is 2 stops underexposed, then boost it +2 in post, the resulting JPEG file is actually ISO 400 (according to the ISO standard).
If you take an "ISO 1600" raw file that is 2 stops overexposed, then cut it -2 in post, the resulting JEPG file is actually ISO 400.
In other words, the ISO setting of the raw camera file and the resulting JPEG file can be two totally different things.
The best result is to ETTR then ITTR: expose to the right, then ISO to the right. That is, first increase exposure as much as possible (while avoiding unwanted motion blur, thin DOF issues, etc.), then, if you still have room on the right side of your histogram, increase ISO as much as possible (up to the highest useful limit of the camera, which is 1600 on most Canons). The first part is most important, but the second can have slight benefits too (especially from ISO 100 to 400).
Reply With Quote