multiple exposures to reduce noise?

Discussion in 'Beyond the Basics' started by nakedyak, Mar 4, 2006.

  1. nakedyak

    nakedyak TPF Noob!

    Joined:
    Sep 6, 2005
    Messages:
    451
    Likes Received:
    1
    Location:
    Columbus, OH
    Can others edit my Photos:
    Photos NOT OK to edit
    I've heard of people taking multiple exposures at night to reduce noise. How does this work? Is it something you can do in photoshop? I want to get as much detail as possible out of my pictures with the least amount of noise. I have a 10d, and i dont think it can do that extra dark frame that subtracts from the regular one to reduce noise. Thanks


     
  2. Mohain

    Mohain TPF Noob!

    Joined:
    Dec 29, 2005
    Messages:
    1,863
    Likes Received:
    11
    Location:
    London, England.
    Can others edit my Photos:
    Photos OK to edit
    I don't know about multiple exposures but to try to reduce noise on night shots you should expose to the right.

    Cheers,

    Mohain.
     
  3. markc

    markc TPF Noob!

    Joined:
    Mar 8, 2004
    Messages:
    4,237
    Likes Received:
    6
    Location:
    Rochester, NY Velocity: Unknown
    Can others edit my Photos:
    Photos NOT OK to edit
    The basic idea is to put the lens cap on and take a "dark frame". Just shoot using the same aperture/shutter/ISO that the original was taken in. This should be done soon after, not the next day, so that the temperature is the same, etc.

    In Photoshop, copy the darkframe over the original as a layer (shift+drag to keep alignment if you do it with the mouse). Change the layer mode to "difference". This should remove the parts that are the same (the noise). I haven't tried it myself.
     
  4. Unimaxium

    Unimaxium TPF Noob!

    Joined:
    Nov 13, 2004
    Messages:
    2,689
    Likes Received:
    22
    Location:
    Northeastern University, originally from Philly
    Can others edit my Photos:
    Photos OK to edit
    There's also the technique to take multiple shots of the same scene and then stack them together in Photoshop. I know this is done often in astrophotography. PlasticSpanner should probably know more information about this technique.
     
  5. nakedyak

    nakedyak TPF Noob!

    Joined:
    Sep 6, 2005
    Messages:
    451
    Likes Received:
    1
    Location:
    Columbus, OH
    Can others edit my Photos:
    Photos NOT OK to edit


    Thanks for the advice. I was looking for an answer more along the lines of Unimaxum's, but i'll try all of them.
     

Share This Page