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Sony SLT-A58 Autofocus Problem

Discussion in 'Sony Chat' started by Hibbster, Oct 20, 2014.

  1. Hibbster

    Hibbster Member

    Does anyone know how to lock the autofocus on centre. I am using a Sigma 150-500mm lens for bird watching. Yesterday I'm zoomed fully in with a bird in centre of the frame and nothing other than sand and water to the left, right, above and below. When I squeeze the trigger the green focus boxes are flashing on 2 points either side of the bird. Why does my camera think I want to focus on the water when I've obviously got the main subject in the middle of the frame? Am I missing something? There must be a way to switch off this function and focus solely on what is in the middle of the frame. Any ideas?
     
  2. nimbus

    nimbus Well-Known Member

    The focusing on most cameras is programmed to lock onto the closest point, but is also centre biased. The result most of the time is thus focus on the centre or slightly to the right and left, with a long lens there is little leeway in focus. Importantly are the images you are shooting sharp?

    I do have an A57 and there doesn't appear to be any means of choosing the focusing point, this camera is from the same series as your A58.
     
  3. Hibbster

    Hibbster Member

    The problem I had is that I couldn't get the camera to autofocus on my subject without doing it manually. Obviously that's not ideal when you are photographing birds as they don't normally hang around long enough for you to mess about. It happened several times and I missed some good shots because of it. Yes the images are sharp but not where I want them to be sharp. They were focusing on points either side of my target. Maybe I am expecting too much Nimbus. Thanks for your help though.
     
  4. neilt3

    neilt3 Well-Known Member


    Read page 110 of the user manual .

    http://pdf.crse.com/manuals/4459705121.pdf

    Set it to SPOT if you want the centre spot only to A/F .
    Set to LOCAL if you want to chose any of the other 14 positions.

    Using ZONE or WIDE is just leaving things to chance.

    Auto focus can be set for CONTINUOUSE , SINGLE SHOT , AUTOMATIC and MANUAL .

    Same goes for the a57 , you have full control of how your camera's work.
     
  5. Hibbster

    Hibbster Member

    Perfect.:eek: I am an idiot! Thanks for your help
     
  6. Hibbster

    Hibbster Member

    Amazing photos by the way Neil. You are obviously from my neck of the woods!
     
  7. neilt3

    neilt3 Well-Known Member

    Your welcome and thanks' for the compliment .
    Are you from the North West too ?


    If birding's your thing , are you shooting in aperture priority mode or shutter priority mode rather than programme or auto ?
     
  8. Hibbster

    Hibbster Member

    Yes, Warrington. I usually go to Moore and Woolston Eyes. I got my Sigma 500m last week so I'm very much on a learning curve and still trying to understand all the terms. I had been shooting in Auto but will change now as I don't think the spot focus works in Auto. I need to experiment I think.
     
  9. nimbus

    nimbus Well-Known Member

     

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