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MIrror Lenses?

Discussion in 'Help Team' started by whitbycolin, Oct 10, 2003.

  1. whitbycolin

    whitbycolin Well-Known Member

    Hello, not wishing to appear a freshman but can anyone describe what a 'mirror lens' is and what pros and cons there are to such a lens? I have been offered a '600?' mirror lens and whilst the focal length seems impressive it seems quite remarkable. I understand that the quality will not match a prime lens of such focal length, however in my favour neither does the price.

    I would welcome your comments.

    Cheers
     
  2. Canonball

    Canonball Well-Known Member

    Take a look here to see the basic design of a mirror lens.

    The advantages of the design are reduced size and weight, and a much lower price, compared to a conventional design of the same focal length.

    The disadvantages are a fixed aperture, typically f/8, although some are f/5.6, and limited performance compared to a conventional design, although some are better than others.

    I have a Centon 500mm, which, if it was a bit heavier, would make a decent paperweight. Otherwise, it's dreadful.

    Geoff
     
  3. wideangleman

    wideangleman New Member

    There is another problem with mirror lenses, namely thay are a little more fragile than refracting lenses. One heavier than average knock can disturb them and so it is always best to put a test film through the camera before writing the cheque. Apart from the fixed aperture , which is usually compensated for by the ND filter that comes with the lens, I have found them quite useful, do not forget however that although the lens is smaller than a normal 600mm lens the problem of camera shake is still alive and well.
     
  4. parisian

    parisian Well-Known Member

    That is insulting to paperweights Geoff. Mine makes a very reasonable doorstop though/img/wwwthreads/smile.gif

    Cohen the Kosher cock[​IMG]
     
  5. Benchista

    Benchista Which Tyler

    If it's a Vivitar Solid State Cat, Bob Shell reckons it's excellent. If it's a Sigma, it's OK. The Centon is a steaming pile of dogshit - no, actually it's not fresh enough to be steaming.

    Nick BSRIPN
    I am a camera.
     
  6. Canonball

    Canonball Well-Known Member

    Well, I did say "if it was a bit heavier" /img/wwwthreads/wink.gif

    Geoff
     
  7. parisian

    parisian Well-Known Member

    And there was me wondering if I should have changed me vest/img/wwwthreads/smile.gif

    Cohen the Kosher cock[​IMG]
     
  8. Nishiki

    Nishiki Member

    It all depends what you want to use it for. If you want to photograph a Tornado at 5000ft comming at you doing 600mph then forget it (I always found focussing a problem with my mirror lens).

    On the other hand should you wish to take shots of landscapes, buildings or slow moving objects like animals in nature parks (who just sit there & look at you) then a mirror lens would be OK.

    The F8 or F11 aperture would also require you to use a film of 400ASA or faster otherwise when the sun goes in, you use another lens or go home!!
     
  9. Col. Hogan

    Col. Hogan Well-Known Member

    I took pictures of planes landing at our local airport in 2000 with a slide film (might have been ISO 200) and a manual focus mirror lens. Though some of the planes are out of focus, I can clearly see the pilot of an F15 in the cockpit as it's landing in some of them. Fast objects can be done with patience and a monopod.

    Diane /img/wwwthreads/smile.gif
     
  10. Lounge Lizard

    Lounge Lizard Well-Known Member

    I managed to see the moon when I had a mirror lens...

    I also got lots of shots of doughnuts...

    To be honest, I tried one and got shot of it not long after. I know the long focal length for a cheap price is pretty tempting but they do really need tripods all the time because of their focal length and f8 or worse fixed aperture. They just aren't practical.

    David
     
  11. ermintrude

    ermintrude Hinkypuff

    lots of shots of doughnuts...

    Mmmmm tasty...

    [​IMG]<font color=purple>ermx</font color=purple>
     

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