Question about Sigma 105mm Macro

Discussion in 'Digital Discussion & Q&A' started by bdavis, Jan 14, 2009.

  1. bdavis

    bdavis TPF Noob!

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    I just got this lens today and I'm trying to familiarize myself with it so excuse me if I ask dumb questions.

    There is a rotating ring near the body with aperature numbers on it, they range from 2.8 - 32. For some reason I have to keep it on 32 because if I switch to any other number my camera says "f/EE" for the aperature which I am taking to mean error. Is this normal behavior for this lens? In my macro photography I can't get an aperature wider than about 5.6 and I would really like to be able to get a bit wider than that for a softer focus.

    Can someone tell me what's up?
     
  2. Overread

    Overread has a hat around here somewhere Staff Member Supporting Member

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    I take it your a Nikon shooter - I think with the aperture rings you set it to one end (As you have found out) and then the camera takes over adjusting the aperture.
    As for getting a smaller aperture (bigger f number) what mode are you shooting in? Aperture priority mode or full manual mode are the best to shoot in

    Try -
    f13 - ISO 200 - 1/200sec (shutter speed) when using your flash.
    If your tripod shooting then you can afford to use a slower shutter speed and will need to to let enough light in
     
  3. bdavis

    bdavis TPF Noob!

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    I am a nikon shooter, I have a D90 with the mentioned Sigma 105. I normally shoot in Aperture Priority or Manual when doing the shots, but it won't let me set my aperture any larger than 5.6 at a 1:1 ratio.
     
  4. Garbz

    Garbz No longer a newbie, moving up!

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    It's a legacy thing. The aperture ring is only relevant on a body which does not digitally control the aperture. For every other body the lens is required to be set to it's minimum aperture to work correctly since this ring sets the mechanical limit and thus the body shows f/EE.

    Imagine the case where the aperture ring is set to f/5.6 the camera is set to f/8. During the exposure the camera has metered for f/8 is set at f/8 but because the aperture ring is entirely mechanical the aperture won't close below f/5.6. This is exactly why the camera will show an error.
     
  5. Overread

    Overread has a hat around here somewhere Staff Member Supporting Member

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    ahh the aperture thing - with macro lenses (and it appears nikon cameras - since canon don't do this - at least for the lower models) the effective apperture decreases as the lens approaches 1:1 magnification. With a canon camera body the camera does not report this and thus you can shoot at f2.8 (even though the camera will meter through the darker spot and thus give you a much slower shutter speed). A nikon camera will report this change in effective aperture change, so your lens is wide open at f5.6 - as wide open as one on a canon camera at f2.8
    (helpfully confusing isn't it)

    edit - link for more info:
    http://www.juzaforum.com/forum-en/viewtopic.php?f=1&t=4595
     

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