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Thread: Needed your help again ... until I read the manual

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    Super Duper
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    Wink Needed your help again ... until I read the manual

    So, today I took delivery of the 14-24/2.8 and 100/2.8VR (both of which I swore I'd never get ... LOL!)

    I go to use the 100 and the darn thing wouldn't let me select f/2.8 ... f/4 was was the best it would give me on any setting , yet another item to send back

    So, before doing that I thought to ask you folks first ... then it dawned on me to read the manual so I don't look to dumb ... sure enough ...PG 23, item #9: "Setting the Aperture" ... "the effective aperture varies with shooting distance" ... I've never heard of such a thing on a fixed prime lens ... what's up with that?

    (Nice lens BTW)

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    Re: Needed your help again ... until I read the manual

    It's rather normal on a macro, at least on Nikon's macros. You probably don't want f/2.8 at macro distance anyway. Even on a tripod, you'll have a hard time getting anything in focus unless you stop breathing

    I assume that it's the same phenomenon that makes some zoom lenses change maximum focal length at close focusing distances. Sony's new, high quality 70-300 lens is said to approach a maximum 200mm focal length when being focused close to it's near limit, which is 1.2 meter.
    Last edited by Jorgen Udvang; 28th May 2008 at 19:13.

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    Re: Needed your help again ... until I read the manual

    Marc,

    Think about how extension tubes work. You put a lens on an extension tube (or bellows) to reduce the minimum focus, but for every x amount of extension you lose y amount of light. Here, with Nikon's design of an internal focusing macro, you are losing light as you near minimum focus. I've seen this on other macro lenses as well. On other camera brands the lens reads the same aperture as what you set it at, you lose light anyway, and the camera's meter compensates. In Nikon land the CPU lens communicates the real T-stop, rather than the set f-stop. (T for actual light transmition, rather than f-stop for focal length to aperture ratio)

    Enjoy your new lenses.

    David
    David Farkas
    Leica Store Miami

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    Re: Needed your help again ... until I read the manual

    Quote Originally Posted by dfarkas View Post
    Marc,

    Think about how extension tubes work. You put a lens on an extension tube (or bellows) to reduce the minimum focus, but for every x amount of extension you lose y amount of light. Here, with Nikon's design of an internal focusing macro, you are losing light as you near minimum focus. I've seen this on other macro lenses as well. On other camera brands the lens reads the same aperture as what you set it at, you lose light anyway, and the camera's meter compensates. In Nikon land the CPU lens communicates the real T-stop, rather than the set f-stop. (T for actual light transmition, rather than f-stop for focal length to aperture ratio)

    Enjoy your new lenses.

    David
    Yep, understand the concept as I've used tubes with a 120 Zeiss for decades ... which is what I suspected, and why I didn't immediately return the lens. It's just that I had never seen it read out on a lens like my 100/2.8 Canon Macro. Interesting ... and thanks for the replies.

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    Re: Needed your help again ... until I read the manual

    Hi Marc
    That takes me back - I have this lens for the second time; the first time (3 years ago?) I found the same thing, took it back to the dealer, who also didn't know about it and rang Nikon - what a palaver!

    Glad you got it sorted. I'm afraid that I'm allergic to manuals as well!

    Just this guy you know

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    Re: Needed your help again ... until I read the manual

    Marc - Don't feel bad, I had the same thoughts when I first got mine. Then focussed farther away and got 3.2, then farther yet and got 2.8. My mind then engaged. It took a minute to overcome mentally what was going on. I believe other lenses also do the same thing, but like David said they just don't tell you.

    Best,

    Ray

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    Re: Needed your help again ... until I read the manual

    Quote Originally Posted by harmsr View Post
    Marc - Don't feel bad, I had the same thoughts when I first got mine. Then focussed farther away and got 3.2, then farther yet and got 2.8. My mind then engaged. It took a minute to overcome mentally what was going on. I believe other lenses also do the same thing, but like David said they just don't tell you.

    Best,

    Ray
    Yanked it out of the box and I never even focused on anything beyond 1' away ... LOL.

    The 2 new lenses are in the wedding bag for this Saturday's 8 hour workout ... wahooooo !

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    Re: Needed your help again ... until I read the manual

    When I was at B&H and could not get it down to f2.8 I was told that it was a DOF issue.... essentially there wasn't any.

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    Re: Needed your help again ... until I read the manual

    Quote Originally Posted by TEBnewyork View Post
    When I was at B&H and could not get it down to f2.8 I was told that it was a DOF issue.... essentially there wasn't any.
    Nothing like making something up in lieu of actually knowing the product you're selling...

    David
    David Farkas
    Leica Store Miami

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