Results 1 to 5 of 5

Thread: Teleconverter and DOF

  1. #1

    Red face Teleconverter and DOF

    i've tried googling, but the answers were mixed.

    my question is, if i add a 1.4 teleconverter to the lens which cuts 1 stop of light, i read that for eg, f5.6 will become f8. but does this change the dof, since the aperture is not physically changed?

  2. #2
    Member
    Join Date
    Jan 2009
    Location
    Bedok
    Posts
    67

    Default Re: Teleconverter and DOF

    Quote Originally Posted by DiGdUb View Post
    i've tried googling, but the answers were mixed.

    my question is, if i add a 1.4 teleconverter to the lens which cuts 1 stop of light, i read that for eg, f5.6 will become f8. but does this change the dof, since the aperture is not physically changed?
    I think dof should be thinner since focal length is longer now.

  3. #3

    Default Re: Teleconverter and DOF

    I'd say it would be the same as the DOF on the equiv. lens.
    Alpha

  4. #4
    Member
    Join Date
    Jan 2009
    Location
    Bedok
    Posts
    67

    Default Re: Teleconverter and DOF

    So if I take a picture from the same spot with:

    (1) 100mm@f5.6, 1/60,
    (2) 100mm+1.4TC@ f5.6, 1/30
    (3) 140mm@f8, 1/30

    (2) & (3) will have the same dof, both will have thinner dof than (1)

    Right?

  5. #5

    Default Re: Teleconverter and DOF

    Quote Originally Posted by DiGdUb View Post
    i've tried googling, but the answers were mixed.

    my question is, if i add a 1.4 teleconverter to the lens which cuts 1 stop of light, i read that for eg, f5.6 will become f8. but does this change the dof, since the aperture is not physically changed?
    Using Sepia's example of a 100mm F2.8 lens, 140mm at F4 would have approximately the same DOF on your image as a 100mm at F2.8.
    The 140mm captures a bigger image of the subject, so somewhat similar to cropping your 100mm pic (not bringing definition in).

    Below is a simple explaination of how DOF works. The one on Wikipedia is too technical (at least for me lol), this is easier to understand.

    http://www.cambridgeincolour.com/tut...h-of-field.htm

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
  •