1. Welcome to NikonCafe.com—a friendly Nikon camera & photography discussion forum!

    If you are thinking of buying a camera or need help with your photos, you will find our forum members full of advice! Click here to join for free!

Kinda Noob Question..

Discussion in 'General Discussion' started by zerocool, Sep 7, 2008.

  1. zerocool

    zerocool

    546
    Jan 21, 2008
    Tracy Calif
    i have a chance to buy a Tamron 500mm F8 Mirror Lens...

    but im confused as to what it means by Mirror Lens...


    someone give me a hand?
     
  2. Spectre

    Spectre

    Feb 20, 2008
    Oregon
    As the name implies these lenses are mainly based on mirrors rather than glass elements. Incoming light gets reflected by a main mirror (located at the back of the lens) towards a small secondary mirror (at the front) which then reflects the light back towards the film via a correction (glass) element.

    Due to the design there are several drawbacks to mirror lenses.

    No aperture so it's not possible to control the depth-of-field.
    The mirror reflections reduce contrast
    The overall sharpness is usually mediocre
     
  3. Lurker

    Lurker

    Jul 21, 2007
    NJ
    Catadioptrics are light, short and give you a large focal length in a small package.

    As Paul pointed out there are some drawbacks. Most of those have more to do with the fact that most CD's on the market are cheap lenses. The hubble uses a mirror and the sharpness is (after nasa fixed it, that is true :rolleyes: ) stunning.

    The biggest problem that you'll find with a mirror lens is that any highlight in the background will be displayed as a donut shape. (Donuts. Is there anything they can't do? - Homer Simpson).

    Here is a wikipedia image that shows exactly what to expect:
    Heron_and_donut_bokeh_20070607.jpg
    Subscribe to see EXIF info for this image (if available)
     
  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.