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[OM] Sony A7 mirrorless FF body announced

Subject: [OM] Sony A7 mirrorless FF body announced
From: usher99@xxxxxxx
Date: Fri, 18 Oct 2013 18:01:05 -0400 (EDT)
Dr. Focus writes:
>>As I was re-reading this it occurred to me to express the tolerances
>>here in another way. The depth of focus (the image side of depth of
>>field) is about 3/4mm or 75 times the stated required precision of 10
>>microns.

Roger at Lensrentals did careful measurements on an optical bench at 
F1.4 and I don't doubt the results.

Recent comment on Ming Thein’s site that mentions: “Don’t think you can 
get away with adaptors: the planarity of such adaptors is going to be 
absolutely critical, especially with such short flange distances and 
resolution numbers. You’ll actually be able to see the effects of a 
cheap, out-of-plane adaptor – it looks a little like a tilt. (I know 
this because I tried Hasselblad lenses on my D800E; none of the three 
adaptors I obtained had sufficiently tight tolerances to avoid this 
problem.)”

He used expensive but 3rd party adapters--OEM might be better. The 
adapters seem to induce a tilt and the physical large size of these for 
these short registration distance cams
magnify the problem. Roger stated he is doing more experiments (in an 
FM thread) with more adapters rotating every 30 deg or so to figure out 
the issues.
That be said, as per Dr. Focus, stopped down a bit, shouldn't matter a 
whole lot.
I hope some adapters will be more precisely engineered though. 
Metabones already has a ver 111 adapter for Canyon EF to FF Sony with 
probable AF and IS working.

Adaptable Mike





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