Lens Specifiaction - Quick Questions

Discussion in 'Beyond the Basics' started by aby, Jan 20, 2005.

  1. aby

    aby TPF Noob!

    Joined:
    Jan 20, 2005
    Messages:
    4
    Likes Received:
    0
    Normally a lens has its specs written as
    35-80mm f/4.0-5.6 or
    50mm f/2.0 Lens
    How does this translate in terms of Focus, Zoom, Aperture etc.

    Also, in the digital world, we get 3x, 4x zoom. How do we convert from 'mm' zoom to 'x' zoom.

    Thanks.
     
  2. Soulreaver

    Soulreaver TPF Noob!

    Joined:
    Feb 12, 2004
    Messages:
    128
    Likes Received:
    1
    Location:
    Sao Paulo, Brasil
    35-80mm f/4.0-5.6
    X zoom 80/35 = 2.2X ( about) :D
    Minimum aperture is 4.0 at 35mm and 5-6 at 80mm ( dark lens)
    No relation to focus

    50mm f/2.0
    X zomm - Not a zoom lens, this one is fixed length.
    minimum aperture 2.0 .50mm generally are 1.4 or 1.8
     
  3. Big Mike

    Big Mike I am Big, I am Mike Staff Member Supporting Member

    Joined:
    Dec 16, 2003
    Messages:
    33,817
    Likes Received:
    1,811
    Location:
    Edmonton
    Can others edit my Photos:
    Photos NOT OK to edit
    The "#X" is a measure of the zoom range. 20mm to 60mm would be 3x zoom. 20mm-80mm would be 4x zoom.

    It's different for each camera. Check www.dpreview.com for specs on most digital cameras. They will list the zoom of a camera and give you what the equivalent would be on a 35mm camera.
     
  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
    You mean maximum aperture...the smaller the number, the larger the aperture. Just a small correction ;)

    And for the original subject... in terms of x zoom,that's not a digital thing, that's a point-and-shoot thing. When you get into cameras with interchangable lenses (digital or film), the focal lengths (mm) of the lenses become important because that tells you how wide the field of view is (when you talk about zoom all that tells you is the comparison of the widest field of view of the lens to the narrowest field of view... for example a 2x zoom means the widest FOV is 2x wider than the narrowest FOV). But if you have a prime (fixed focal length) lens, the zoom would be 0x, since it doesn't zoom, but still a 100mm prime will have a narrower FOV than a 50mm.
     

Share This Page