Results 1 to 2 of 2

Thread: ISO vs RAW brightness compensation

  1. #1
    pwnage101's Avatar
    Join Date
    Jan 2010
    Location
    California, USA
    Posts
    304
    Real Name
    Troy

    ISO vs RAW brightness compensation

    Is ISO in DSLRs done by physically changing the voltage/current in the sensor, or is it post processing done by the camera's CPU to modify the histogram?

    Is it advantageous to make the ISO faster in low light situations with X exposure rather than capture the image at X minus 3 exposure and bump up the exposure by 3 in ACR?

    Thanks,
    troy
    Last edited by pwnage101; 31st January 2010 at 12:24 AM.

  2. #2

    Join Date
    Dec 2008
    Location
    New Zealand
    Posts
    17,662
    Real Name
    Have a guess :)

    Re: ISO vs RAW brightness compensation

    Quote Originally Posted by pwnage101 View Post
    Is ISO in DSLRs done by physically changing the voltage/current in the sensor, or is it post processing done by the camera's CPU to modify the histogram?
    As a rule manufactures don't reveal details, but usually whole ISO steps (100 -> 200 -> 400 etc) are achieved by analog amplification of the signal read off the sensor whereas intermediate steps are done via software (and are thus slightly more noisy). The exception (with Canon anyway) is that the "H" and "L" ISO modes are done digitally.

    Is it advantageous to make the ISO faster in low light situations with X exposure rather than capture the image at X minus 3 exposure and bump up the exposure by 3 in ACR?
    Yes. A correct exposure at a higher ISO will yield less noise than an under-exposed shot at a lower ISO that's adjusted in PP.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •