Results 1 to 3 of 3

Thread: How to calculate depth of field?

  1. #1

    How to calculate depth of field?

    What is the formula for caluclating the depth of field for a given lens focused at a given distance at a given aperture? I don't mean the hyperfocal distance. I need to be able to figure d-o-f for macro work as well as for work at more no rmal subject distances. I now I've seen this somewhere, maybe in of of Adams' b ooks, but I haven't been able to find it. I also recall encountering a web page feature somewhere that would calcucate d-o-f hwne you plugged in lens, aperture and distance data but I can't find that either. Thanks.

  2. #2

    How to calculate depth of field?

    where:

    h=hyperfocal U=object distance

    Near limit (Dn) = hxU/h+U Far limit (Df) = hxU/h-U DOF = Df-Dn

    --Stroebel, "View Camera Technique" pp. 137-138.

    Some URLs related to DOF:

    http://www.worldphoto.com/depthof.htm

    http://www.dof.pcraft.com/dof.cgi

    Hope it helps.

  3. #3

    Join Date
    May 1998
    Posts
    218

    How to calculate depth of field?

    In the quoted source, Stroebel is a bit naughty in not mentioning that these for mulae are approximations. They are increasingly inaccurate for closer distances. Dennis's question was for macro, where a more suitable equation (also approxima te) is:

    T = 2.C.N.(1+m)/(m*m)

    where: T is the total DoF, C is the diameter of the circle of confusion, N is th e f-number, and m is the magnification. The DoF can be assumed to be symmetrical , in other words you have T/2 in focus in front of the sharp point, and T/2 behi nd it. [Focal Encyclopedia.]

    Accurate formulae for distances to near and far points, suitable for any distanc es, are:

    Df = (v - C.N').f / (v - C.N' - f)

    Dn = (v + C.N').f / (v + C.N' - f)

    where v is the image distance, N' is the effective aperture and f is the focal l ength.

Similar Threads

  1. Depth of Field, Depth of Focus, and Film Flatness
    By steve simmons in forum Cameras & Camera Accessories
    Replies: 65
    Last Post: 7-Jan-2006, 19:30
  2. Depth of Field, Depth of Focus, and Film Flatness
    By robc in forum Cameras & Camera Accessories
    Replies: 4
    Last Post: 6-Jan-2006, 14:44
  3. Depth of Field calculation in the field
    By Don Wallace in forum Style & Technique
    Replies: 15
    Last Post: 31-Oct-2004, 16:54
  4. Depth of Field - 4x5
    By Scott Mittelsteadt in forum Style & Technique
    Replies: 16
    Last Post: 1-Dec-2000, 16:37
  5. How are depth of field and depth of focus related?
    By Jeffrey Goggin in forum Style & Technique
    Replies: 13
    Last Post: 16-Nov-2000, 23:21

Bookmarks

Posting Permissions

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