CDAF lenses - question

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  • 05-07-2010, 05:12 AM
    CDAF lenses - question
    I don't understand what a CDAF lens is or what it does in relation to a non-CDAF lens - how it affects images, etc. How do I know if my lenses are CDAF? I thought there was an older thread on this, but nothing came up on search. So thanks for any information.

    Olympus 14-42 kit
    Panasonic 20mm/f1.7

    Olympus 40-150mm
    Olympus 50mm/f2

  • 05-07-2010, 12:33 PM
    Re: CDAF lenses - question
    CDAF - contrast detection auto-focus
    as opposed to
    PDAF - phase detection auto-focus

    CDAF can be done in live view using the imaging sensor
    PDAF uses (many) dedicated autofocus sensors using light reflected off the mirror

    So micro 4/3 can only focus using CDAF.

    My guess is that the autofocus control is shared between the camera's processor and the lens' processor, and that the lens needs the right firmware to be able to work in CDAF mode.

    All lenses are capable of AF with the E-P1, I suspect with the E-PL1 too.
    "the EP1 AF works with all Four Thirds SLR lenses (though it is probably very slow with the older 4/3 lenses, not designed specifically for CDAF)"
    "I think that as E B said it has been a bad internet rumor that SWF lenses could not be CDAF compatible."