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Minor Issue With 200Mm Macro


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#1 erineamer

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Posted 07 July 2016 - 12:12 AM

I have an AF Micro-Nikkor 200mm f/4D IF-ED lens, used on a d7100. Sometimes will only go to f4.2, sometimes to f4. otherwise seems perfect. User error, or something that needs fixing somehow, or not an issue if f4 vs f4.2 isn't a big deal- because it's not really. Seems to happen when the subject is very close to the lens, not an issue when a bit farther away.

Thanks for taking a look!



#2 TrailEx

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Posted 07 July 2016 - 03:02 PM

I don't know anything about that lens, but if its listed as a constant aperture, it should be able to shoot at F/4 at any time. Sounds like a lens problem, but as you said a pretty minor one. Up to you if you want to get it fixed or replaced...I probably wouldn't bother unless theres something else wrong or you have it under warranty still



#3 JestePhotography

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Posted 07 July 2016 - 08:50 PM

Try cleaning the contacts.

#4 erineamer

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Posted 08 July 2016 - 08:22 AM

Will do, thank you!



#5 erineamer

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Posted 08 July 2016 - 03:20 PM

I asked on another forum, and got this as an answer

 

Nikon micro lenses report effective aperture to the camera. The formula for effective aperture is:

Effective F-Stop = Physical F-Stop x (1 + Magnification / Pupil Magnification)

which, upon paying more attention when testing it out, seems to be what's going on- just thought I'd put it here in case anyone was interested






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