E-M1 PDAF Questions

Discussion in 'Olympus Cameras' started by daanh, Jul 26, 2015.

  1. daanh

    daanh Mu-43 Regular

    Jul 25, 2010
    Hi, I would like to know more about PDAF on the E-M1.

    - Is PDAF only used when using old 4/3 lenses?

    - How many PDAF points does the camera actually have?

    - Is there a setting that will autofocus constantly and acceptably when shooting video with a 25mm 1.4 lens? Can the the PDAF help here in any way?

    Thanks, Daan
  2. Andym72

    Andym72 Mu-43 Veteran

    Mar 4, 2013
    Reading, UK
    1. No. It's definitely used with m43 lenses, in a hybrid PDAF + CDAF mode, if you switch to Continuous AF setting. There is some talk that with each later firmware, Olympus have extended the use of this hybrid mode to other AF settings.

    2. 37

    3. Not big on video, sorry.
  3. Luckypenguin

    Luckypenguin .

    Oct 9, 2010
    Brisbane, Australia
    Real Name:
    Unfortunately the EM-1 doesn't utilise hybrid autuofocus with 4/3 lenses; it only uses PDAF.
  4. daanh

    daanh Mu-43 Regular

    Jul 25, 2010
    I don't understand why a lens should be for one type of autofocus or another. Is there a fundamental difference between a PDAF and CDAF lens?
  5. Phocal

    Phocal Mu-43 Hall of Famer

    Jan 3, 2014
    A very big difference. On my phone so not going to get into it now. Maybe someone will come along before I get home to explain
  6. edmsnap

    edmsnap Mu-43 Veteran

    Dec 20, 2011
    Edmonton, Alberta
    Yes. The lens motor for PDAF just needs to speed from point-A to point-B as PDAF measures and generates a distance to the subject. The motor for a CDAF lens doesn't have a specified distance to travel, it zooms along the range until contrast gets worse, then reverses direction until contrast gets worse again, the reverses direction again... and keeps doing that until reversing direction doesn't make the contrast any better. When a PDAF lens is used with a CDAF focussing system, it can focus just fine, but the motor isn't made to do the rapid back-and-forth focus swings so it goes much slower. A CDAF-designed lens has no issues with PDAF focusing. Because there's a single focusing motion, PDAF systems usually focus faster. Because it repeatedly measures the actual scene being focused, CDAF systems usually focus more accurately.

    To the OP, Olympus describes the answer you're after here.
  7. Clint

    Clint Mu-43 All-Pro

    Apr 22, 2013
    San Diego area, CA
    Real Name:
    Acceptably is up the user. Videographers I know are prone to use manual focusing even if using $35K gear. It does not matter if PDAF could help or not since we don't have any options for use of it.
  8. daanh

    daanh Mu-43 Regular

    Jul 25, 2010
    Thanks! That's really helpful!
  9. VooDoo64

    VooDoo64 Mu-43 Veteran

    Jul 17, 2010
    Zagreb - Croatia
    Real Name:
    Davor Vojvoda
    I'm interested in whether E-M5mk2 have a better C-AF and AF-tracking ( with micro 4/3 lenses ) or E-M1 have better or the same ??

    I looked up some review for EM5-mk2 on youtube and E-M5mk2 have almost perfect C-AF on m43 lenses ?!