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infinity focus problem with 50/1.4 at f 2.8 and wider

 
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wayne_s



Joined: 24 Jun 2009
Posts: 7

PostPosted: Sun Feb 14, 2010 5:36 am    Post subject: infinity focus problem with 50/1.4 at f 2.8 and wider Reply with quote

Hi Conurus,

I seem to have noticed a problem where my N 50 1.4 lens doesn't properly focus at infinity at apertures f2.8 and wider.
It doesn't even focus when manually focusing either.
Wondered if my mount is too thick?
My lens is very sharp when subject is closer than infinity distance at wide apertures. And with the micro-adjust the AF is spot on and perfect.
Normally, if I am taking distant landcape shots I use f5.6 or narrower apertures which work fine.Just discovered this problem while doing some lens testing.

Thanks,

Wayne
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conurus
Site Admin


Joined: 15 Aug 2006
Posts: 795
Location: Vancouver, Canada

PostPosted: Sun Feb 14, 2010 8:09 am    Post subject: Reply with quote

Hi Wayne,

I looked at the lens database and your lens had a 0.03mm shim inside which if taken out I think will address the problem. Please feel free to send it back and we will do the work.

We do not know why. We assume Zeiss' calibrations to be correct and we replicated that to an error of only +0.007mm for your lens which is significantly lower than the photographic industry's typical tolerance of 0.02mm for mount thickness. It is possible however for compound tolerances to add up - for example both the lens and the camera body have slightly thicker mounts but still within tolerance.

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I am a bird and I uncovered the E, EF and N-mount communication protocols!
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wayne_s



Joined: 24 Jun 2009
Posts: 7

PostPosted: Tue Feb 16, 2010 6:19 am    Post subject: Reply with quote

Hi Conurus,

Is this something easy that I could maybe do or should I send it to you to do and check out?
What would be the expected turn-around time to do the fix?

Thanks,

Wayne
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