D800 focus with 1.4 prime lenses is very variable and inaccurate

Started Jan 20, 2013 | Discussions thread
Timbukto
Senior MemberPosts: 3,079Gear list
Like?
Re: I'm not surprised.
In reply to moving_comfort, Jan 21, 2013

As a 5DMKII Canon shooter who shoots fast primes, I don't see a big issue here. I think its just some of you guys finally getting used to extracting more MP from lenses. In fact maybe thats where a lot of the Canon's can't focus that well belief spread...because they jumped onto the MP train first. DxOMark thinks you only get about 12 perceptual MP from say a 85mm 1.4G with the D700. Yet the D800's get 11MP's already out of a super zoom in the 28-300.

The absolute *latest* 5DMKIII + certain lenses like the 300mm f2.8 IS II can achieve CDAF-like performance in PDAF...which is a true accomplishment for the pixel peeper. Otherwise for our typical fast primes that are older in design, the variation in focus is a fact of life.

Speaking of renting gear to test for yourself...Roger of LensRental has already done *many* tests of both Canon's AF system as well as Nikon's. Basically variation in focus is inherent in PDAF systems *except* for certain combinations of really expensive Canon gear.

My interpretation of Roger's results is that although the D800 looks to have a slightly higher variation spread in PDAF compared to the D700...it also has the much higher resolution on the same lens which easily may account for essentially 'magnifying' the deviation in sharpness.  Regardless its overall image IQ and not pixel peeping IQ is *much* better.  You are just seeing what we've always known about PDAF (except for whatever Canon has secretly cooked up for certain combinations of very recent gear at least).

Links -

http://www.lensrentals.com/blog/2012/07/autofocus-reality-part-3a-canon-lenses

http://www.lensrentals.com/blog/2012/09/autofocus-reality-part-4-nikon-full-frame

 Timbukto's gear list:Timbukto's gear list
Canon EOS M Canon EOS 6D Canon EF 50mm f/1.4 USM Canon EF 85mm f/1.8 USM Canon EF 200mm f/2.8L II USM +1 more
Reply   Reply with quote   Complain
Post (hide subjects)Posted by
Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark post MMy threads
Color scheme? Blue / Yellow