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CDAF front-focus with 4/3 lenses?

Discussion in 'Olympus Cameras' started by dhazeghi, Jul 17, 2012.

  1. dhazeghi

    dhazeghi Mu-43 Hall of Famer

    Aug 6, 2010
    San Jose, CA
    Dara
    I saw some odd results on my first outing with the E-M5 and the (4/3) 12-60, so I took the opportunity this morning to grab as many shots as possible of detailed subjects.

    At the 12mm end, results were almost all good. But at the 60mm end, I saw a significant number of shots where the plane of focus was clearly in front of the point that I'd placed the AF point on - whether that was 15 feet away, or at infinity. In some cases, it was far enough in front that nothing in the image was really in focus. Overall, I'd say nearly 1/3 of the shots I took at the long end suffered from this.

    Has anybody else seen this sort of behavior? My native lenses seem immune from this (to be fair the 14-42 is soft enough at 42mm that a slight misfocus is almost undetectable).

    Thanks,

    DH
     
  2. Promit

    Promit Mu-43 All-Pro

    Jun 6, 2011
    Baltimore, MD
    Promit Roy
    I've seen MAJOR misfocus but never slight ones that I can remember. This is with the CDAF-optimized 14-54mm.
     
  3. dhazeghi

    dhazeghi Mu-43 Hall of Famer

    Aug 6, 2010
    San Jose, CA
    Dara
    My sample size isn't that large (about 15 OOF shots at 60mm) but I'd say almost half are sufficiently in focus that at 50% magnification they'd look okay. Here is one example (original version is full-sized).

    Of course there are also ones that are no good at all, even at 33%.

    DH
     
  4. dhazeghi

    dhazeghi Mu-43 Hall of Famer

    Aug 6, 2010
    San Jose, CA
    Dara
    Still happening with some regularity. Aside from chimping every shot, I'm not quite sure what the fix is.

    Does anybody have experience with other 4/3 lenses that have this problem (or generally misfocusing)?

    It's annoying, as when the 12-60 is on target, it is very nice and sharp.

    Thanks,

    DH
     
  5. dhazeghi

    dhazeghi Mu-43 Hall of Famer

    Aug 6, 2010
    San Jose, CA
    Dara
    Going back through the last few month's shots, it seems to be primarily a problem at the telephoto end (there is the occasional odd wide-angle shot that's off, but that's far rarer). And in pretty much every case, the focus has been way too close (front-focus). I've also ruled out camera bodies (happens on both the E-PM1 and E-M5).