close

Privacy guaranteed - Your email is not shared with anyone.

Focal length vs lens length

Discussion in 'Through-the-Lens Club' started by MrsKitty, Aug 19, 2006.

  1. MrsKitty

    MrsKitty

    Joined:
    Mar 23, 2003
    Messages:
    18,802
    Likes Received:
    31
    Location:
    >^..^<
    OK, this may sound stupid but you all know me :)

    How does focal legnth relate to lens legnth?

    I have noticed lenses that are half the legnth of another yet twice the focal legnth. Is the physical legnth determined by the number of elements which in turn determines space necessary to hold them inside the lens rather than by focal legnth?

    Did that make any sense?
     
  2. Hokie

    Hokie NRA Member

    Joined:
    May 16, 2006
    Messages:
    515
    Likes Received:
    0
    Location:
    VA
    The focal length listed on the lens is the effective focal length. Modern lens design let the lens be shorter then the focal length. The more elements a lens has then to more space it will take up I do not know of any other reason for lenses of the same Focal length to be different lengths.
     

  3. MrsKitty

    MrsKitty

    Joined:
    Mar 23, 2003
    Messages:
    18,802
    Likes Received:
    31
    Location:
    >^..^<
    Thanks! :)

    I know, I wonder about the most off the wall things :freak: