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Normal Behavior for GX1 and 20mm Lens?

Discussion in 'Panasonic Cameras' started by Cassady, May 4, 2012.

  1. Cassady

    Cassady New to Mu-43

    9
    May 4, 2012
    I recently got a GX1 and earlier this week I received a 20mm lens to go with it. I had been using the 14mm lens previously.

    When I put the 20 on my camera, I got a message telling me to switch to "AFS" focusing, which I did. Now, when I'm out walking around with the camera turned on, lens cap off, I notice the lens focusing from time to time until the camera goes into sleep mode. The lens is also slower to focus than the 14.

    This happens when I don't have the shutter button pushed half way which is where I'd expect the lens to focus.

    The reason I'm concerned about this is that the battery life seems quite a bit shorter when using the 20 than when using the 14. The results from the 20 seem fine--in focus and good looking, but I was wondering if this pretty constant focusing is normal for the 20mm lens.

    TIA
     
  2. WoodWorks

    WoodWorks Mu-43 Regular

    180
    Oct 10, 2011
    Ashland, OR USA
    David
    I just tried it with my GX1/20mm combo, and mine doesn't do what you describe (other than telling me to switch to AFS when I mount it). Unless you're inadvertently half pressing the shutter when you're walking around, I can't think of a reason why it would do that.
     
  3. Sawfish

    Sawfish Mu-43 Regular

    70
    Nov 11, 2011
    Denmark
    • Like Like x 1
  4. mzd

    mzd Mu-43 Veteran

    241
    Nov 30, 2010
    Wisconsin
    i don't have a GX1, but i know the GF1 as a "pre AF" option in the custom menu that basically tells the camera to start focus as soon as the body stops moving. this is different from AFC, which, as mentioned is not available with the 20mm. i don't use pre AF, but it sounds like it could cause the issues you are describing if the GX1 has a similar function.
     
    • Like Like x 3
  5. KVG

    KVG Banned User

    May 10, 2011
    yyc(Calgary, AB)
    Kelly Gibbons
    My 20 does the same thing on my gf1, so do all my other primes(14/25/45) for that matter. I think you just notice it more due to barrel movement on the 20.
     
  6. WoodWorks

    WoodWorks Mu-43 Regular

    180
    Oct 10, 2011
    Ashland, OR USA
    David
    I think you nailed it, mzd. On the GX1 it's a menu item in the REC menu called Q-AF. I had mine off, so it didn't prefocus. But once I turned it on, the camera started behaving exactly like Cassady's. Well spotted!

    David
     
    • Like Like x 1
  7. Cassady

    Cassady New to Mu-43

    9
    May 4, 2012
    Thanks! That was it. I turned off the quick AF function and the lens only focuses now when I press the shutter release half way.

    I actually like the quick AF, but it seems to eat my battery with this lens.