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lensrentals series on AF

Discussion in 'Open Discussion' started by WT21, Aug 1, 2012.

  1. WT21

    WT21 Mu-43 Hall of Famer

    Feb 19, 2010
    Boston
  2. b_rubenstein

    b_rubenstein Mu-43 All-Pro

    Mar 20, 2012
    Melbourne, FL
    I already know this from using LV on my D7000, and the consistently more accurate AF of my ยต4/3 cameras.

    BTW, Canon's tech guy, Chuck Westfall once posted on the Canon AF system, and it is a hybrid closed/open loop control system.
     
  3. addieleman

    addieleman Mu-43 All-Pro

    Aug 5, 2010
    The Netherlands
    Ad
    Not following it, but read it after your heads-up, thanks. I'm not surprised at what I've read. Short summary: PDAF accuracy varies. Roger talks about micro-adjustment which was called AF fine-tune on my Nikon D300s. My experience concurs with the articles: also after micro-adjustment there is variability between shots in focussing accuracy with PDAF with the same lens. I often used to shoot a few pics just to pick the sharpest one afterwards.

    Roger Cicala did not mention the problems you can have with zoom lenses on a DSLR. The optimal AF fine-tune on my D300s would generally vary across the zoom range, which made a Nikkor 12-24mm unusable for me. The Tokina 11-16mm was a little bit better, but not enough. Mind you, I guess there's a lot of sample variation involved here. The Nikkor 70-300/4.5-5.6 VR lens was the only lens that focussed really well, after an AF fine-tune adjustment. IIRC some Olympus DSLR's enable different adjustments across the zoom range, that may alleviate the problem to a certain extent.

    These AF problems are the main reason I won't consider a DSLR again. I still am kind of exhilarated that pictures are focussed accurately each and every time on the G1 and GH2, unless I have done something wrong (which is kind of hard to do). And using MF lenses on them is a dream, I've never been able to focus even as remotely accurately before. For the record: I'm an avid pixel-peeper, I want things to be sharp at 100 % viewing, so that I can print big if I want to.
     
  4. BarefootPilgrim

    BarefootPilgrim Mu-43 Top Veteran

    517
    Dec 23, 2009
    Westchester, IL
    Bob
    The Olys that do have this feature are the E-3, E-30, E-620 and E-5. And it does help -- alot :eek: -- on my E-620 and E-5.

    :thumbup::thumbup:
     
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