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Thread: 105mm 2.8 D macro doubts

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    Senior Member Rawfa's Avatar
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    105mm 2.8 D macro doubts

    Hey guys,

    Just got the old Nikon 105mm 2.8 D macro and there's something bugging me about it. Even though I have everything set to manual, the aperture keeps changing by it self. It lets me close it down, but depending on the circumstances it won't let me open it up...which sucks because I got it partially for it's f2.8 apperture. Any thoughts?

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    Re: 105mm 2.8 D macro doubts

    I do not think the aperture keeps changing by itself!

    This is an old "non-issue" with Micro Nikkors.

    The aperture value you get to see in the camera is the effective aperture (see: http://www.cambridgeincolour.com/tut...cro-lenses.htm) that varies according to the magnification at which the lens is used.
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    Senior Member Rawfa's Avatar
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    Re: 105mm 2.8 D macro doubts

    I cannot open the link you've posted, but are you saying that even if I set the aperture to f2.8, if I get closer to a subject then the camera will adjust the aperture? Is this a thing with ALL Nikon macros? Because if it is I will just trade this lens for a Tamron 90mm f2.8 instead.

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    Re: 105mm 2.8 D macro doubts

    With best regards, K-H.
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    Re: 105mm 2.8 D macro doubts

    Quote Originally Posted by Rawfa View Post
    I cannot open the link you've posted, but are you saying that even if I set the aperture to f2.8, if I get closer to a subject then the camera will adjust the aperture? Is this a thing with ALL Nikon macros? Because if it is I will just trade this lens for a Tamron 90mm f2.8 instead.

    http://www.cambridgeincolour.com/tut...cro-lenses.htm


    f/2.8 for any lens (be it Nikon, Tamron, Otus) is only f/2.8 at infinity.

    At 1:1 magnification it is f/5.6 (though you have set it wide open). It is the law (of Physics). Only Nikon records it as it is.

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    Senior Member Rawfa's Avatar
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    Re: 105mm 2.8 D macro doubts

    Thanks, Vivek.
    Maybe it's because this is an older model, but I was doing some tests where my wife was like 50cm in front of me and the lens would still close down to f3.0

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    Re: 105mm 2.8 D macro doubts

    Quote Originally Posted by Rawfa View Post
    Thanks, Vivek.
    Maybe it's because this is an older model, but I was doing some tests where my wife was like 50cm in front of me and the lens would still close down to f3.0
    "Finally, it's important to note that Nikon cameras automatically correct for the effective f-stop. In other words, the f-stop that is reported in your Nikon camera's viewfinder/LCD will increase progressively as your focusing distance decreases even if you never specifically changed the f-stop setting using standard methods."

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    Senior Member Swissblad's Avatar
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    Re: 105mm 2.8 D macro doubts

    This is an issue with all macro lenses - the closer you focus - the smaller the aperture gets

    Refer to http://blog.mingthein.com/2012/07/27...akro-planar-t/

    See comments section

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    Senior Member Swissblad's Avatar
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    Re: 105mm 2.8 D macro doubts

    Here is a good explanation of this phenomenon

    http://www.cambridgeincolour.com/tut...cro-lenses.htm

    scroll down on section: LENS EXTENSION & EFFECTIVE F-STOP

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