Aperture issues

Discussion in 'Beyond the Basics' started by ajmall, Jul 2, 2005.

  1. ajmall

    ajmall TPF Noob!

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    I have a 24mm F/2.8 Macro film lens but when I put it on my D70s the widest aperture is F3?! I have re attached the lens and still the same and the aperture ring is locked at 22 which it needs to be to work.

    Anyone know what the problem is?
     
  2. ajmall

    ajmall TPF Noob!

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    Does no-one know then?
     
  3. SLOShooter

    SLOShooter TPF Noob!

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    Can you manually open it up to 2.8?
     
  4. Artemis

    Artemis Just Punked Himself

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    is it a non zoom lens? if so then I dont know, if its a zoom lens, zoom right out and then change aparature....
     
  5. kfoster

    kfoster TPF Noob!

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    Assuming that this is not a internal focus lens, but instead one that the front of the lens moves in and out as you focus. Yes?

    I'm not positve but what I think is happening is that when the lens foucs toward 1:1 the lens loose some ability to caputure light. When you focus toward infinity you should get f/2.8. My 105mm f/2.8 Nikkor micro will only get f/5 when focused to 1:1 but easily achieves f/2.8 at infinity.

    K
     
  6. ajmall

    ajmall TPF Noob!

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    it's non internal yes.

    it's a Sigma 24mm F2.8 Marco "Super wide" II. I've tried it on Manaul, AP and SP modes and the widest i can get is F3. I'm rather miffed...
     
  7. airgunr

    airgunr TPF Noob!

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    I'm wondering if it has anything to do with the Magnification factor on the digital cameras. Is the reading for the f/stop on the display? Or, is it on the lens ring it'self? I think it may be that the digital image sensor in giving a magnification factor may decrease the percieved apature as well.

    Just a guess, I may be totally wrong.
     

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