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Thread: Continuous AF on A900

  1. #1
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    Continuous AF on A900

    I don't often use continuous AF, but needed it at the weekend chasing a 9 year old on a swing. I switched to continuous and then nothing happened. It locks, confirms focus and stops exactly as in single shot. As an old CF4 Canon user, I have AF disabled on the shutter button (beats me how you can work with it enabled), so I activated shutter button AF and continuous now works.

    To my simple mind, that is a bug. If I can disable shutter button AF for single shot, why not for continuous? If I am missing something, I would dearly love to be shown how to get it going.

    I have also had a very rude awakening with Sony. With Canon, I had CPS that I could go to. I'm not aware of a Sony equivalent. I rang a number that I was given of a tech guy in Sony, but he hasn't bothered to return my call after 2 days. I hope that this experience is not typical of Sony generally. It make me appreciate how great Hasselblad is in their customer dealings.

    Cheers,

    Jeff
    Last edited by Jeffg53; 11th August 2009 at 01:28. Reason: Signature

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    Senior Member Braeside's Avatar
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    Re: Continuous AF on A900

    I can confirm that with AF with shutter set to OFF, AF Continuous does not function. Pressing the rear joystick only does a Single AF.

    Cannot comment on Sony service as I have never had to call them, but I don't expect much from them in the UK. Most questions I may have are easier answered by asking on excellent forums like this one.
    David Anderson

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    Re: Continuous AF on A900

    Thanks David. I wonder if Sony monitors fora like this. It may be the only way that they find bugs in their firmware. This is a pretty basic bug, and certainly not how Canon cameras behave.

    Cheers,

    Jeff

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    Senior Member Braeside's Avatar
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    Re: Continuous AF on A900

    Jeff, I think many folks wished there was a way to get feedback directly to Sony on this kind of thing.

    There have been some strange things that photographers consider as bugs since Minolta days that have been commented on over and over again in many serious forums and Sony (or previously Minolta) have never fixed them.

    Whether it is a case of arrogance or ignorance we just don't know.

    I'm afraid I just have to put up with these foibles and learn other ways of doing things.
    Last edited by Braeside; 11th August 2009 at 05:00.
    David Anderson

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    Re: Continuous AF on A900

    Thanks David. At least I now know what I am dealing with. As a new kid on the block, I had hoped for better but that is starting to look like naivety.

    Maybe someone should start a Fake Chuck Westfall blog for Sony.
    Cheers,
    Jeff
    www.jeff-grant.com

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    Re: Continuous AF on A900

    Interesting. Do you have the same problem with the A mode? My understanding is it functions like Canon's AI Servo. The idea is you focus on an object, lock focus, and the camera will track it when it moves. Not sure if it will work/lock focus on an object already in motion.

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    Senior Member Braeside's Avatar
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    Re: Continuous AF on A900

    Bill A mode seems to do very little for tracking moving objects. I tried for example focusing on something and lock focus with shutter button half press then move camera a bit back or forward and the image just stays out of focus.

    Incidentally you can also program the A mode setting to instead enable DMF mode so that with lenses that don't have SSM and full time manual already, you can focus manually after auto-focus lock without switching to manual focus first.
    David Anderson

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    Re: Continuous AF on A900

    Quote Originally Posted by Jeffg53 View Post
    I don't often use continuous AF, but needed it at the weekend chasing a 9 year old on a swing. I switched to continuous and then nothing happened. It locks, confirms focus and stops exactly as in single shot. As an old CF4 Canon user, I have AF disabled on the shutter button (beats me how you can work with it enabled), so I activated shutter button AF and continuous now works.

    To my simple mind, that is a bug. If I can disable shutter button AF for single shot, why not for continuous? If I am missing something, I would dearly love to be shown how to get it going.

    I have also had a very rude awakening with Sony. With Canon, I had CPS that I could go to. I'm not aware of a Sony equivalent. I rang a number that I was given of a tech guy in Sony, but he hasn't bothered to return my call after 2 days. I hope that this experience is not typical of Sony generally. It make me appreciate how great Hasselblad is in their customer dealings.

    Cheers,

    Jeff
    Jeff,

    I think the problem arises from difference in terminology. There is no "disable the AF from shutter button" but rather, disable the AF (completely). If the AF is enabled it will AF (whether in continous, single, or AF-A where the camera makes the decision for you if it will do single shot or continous AF).
    If you press the AF/MF (and it is in toggle mode). Also the tracking works well if the camera is in wide focus mode, but not so great if you are using single point AF.

    I hope that helps,

    Cheers,

    N
    A and E mount Too many lenses.

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    Re: Continuous AF on A900

    Recording menu 3 has AF w/shutter as an option. The text says that setting it to off disables AF on the shutter button and assigns it to the multi-selector. With that option selected, continuous AF does not work from the multi-selector. When you press it it acts as a single focus.

    I also have the AF/MF button assigned to AF as that is the same position that it is on Canon bodies, and is very easy to use. I have the custom button set to AF/MF.
    Last edited by Jeffg53; 11th August 2009 at 22:39. Reason: clarity
    Cheers,
    Jeff
    www.jeff-grant.com

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    Re: Continuous AF on A900

    I was contacted by the Sony tech that I had been trying to contact today. He had been on holidays, and rang me on his first day back. We discussed the problem and agreed that it is a bug. He will report it back to the mothership.

    Whether it ever gets fixed or not is anyone's guess but having worked for a large Japanese company in the past, I can understand his position.

    End result is that Sony will officially know they have a problem, and I have been treated well by the local folks. Other than a fix, I guess that I can't expect much more. I hope that Sony will establish a professional support organisation at some time. They have a great product, but I'm not sure that I would like to be dependent on their current support if I were making a living with it.
    Cheers,
    Jeff
    www.jeff-grant.com

  11. #11
    Shelby Lewis
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    Re: Continuous AF on A900

    I never could get continuous AF to work worth a damn with the a900... one of the only things I don't miss about the a900. I had many frustrating moments shooting action @ weddings with it...

    I came to the conclusion that it was not the tool for those situations... kinda like a medium format camera in a 35mm body.

    If it is actually a bug and they can get the continuous AF to be as responsive as the rest of the camera... I'll jump for joy .

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    Senior Member Braeside's Avatar
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    Re: Continuous AF on A900

    Shelby, although I have not attempted to shoot weddings, I have shot high speed waterskiers and other moving objects with continuous AF on the A900 and it worked fine for me. I didn't have AF with shutter OFF.
    David Anderson

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    Re: Continuous AF on A900

    Quote Originally Posted by Shelby Lewis View Post
    If it is actually a bug and they can get the continuous AF to be as responsive as the rest of the camera... I'll jump for joy .
    If it's actually a bug, it should be fixable with a firmware upgrade. Here to hoping.

  14. #14
    Shelby Lewis
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    Re: Continuous AF on A900

    Quote Originally Posted by Braeside View Post
    Shelby, although I have not attempted to shoot weddings, I have shot high speed waterskiers and other moving objects with continuous AF on the A900 and it worked fine for me. I didn't have AF with shutter OFF.
    Hey David... were they, by chance coming at you are were they moving parallel to you? I have several fantastic shots of kids swinging and I was able to focus fine when parallel to me... the few great shots I got with them swinging at me was all due to "decisive moment" photography... in that they would "stop" at the top of the arc for an almost imperceptible moment.

    Gotcha.

    But if I went with continuous af and just tried to track... no dice.

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    Senior Member Braeside's Avatar
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    Re: Continuous AF on A900

    Shelby, admittedly my shots were generally of more distant high speed objects but some of them were coming straight at me at 30 mph and possibly more if the skier was crossing the wake of the boat towards me.

    In this one I was using the A900 and the 70-400G at 400mm f7.1 and DOF was pretty narrow. I am on the shore, not on the boat!



    This one is at 250mm f/6.3



    200mm f/6.3 100% crop



    I used AF-C with Focus priority not Shutter priority, so in theory it should only fire when something, hopefully my target, is in focus.

    I need to test with closer moving objects like you would have in a wedding scenario. Perhaps the servo/lens cannot move fast enough in those situations, and also the DOF at close range will be much shallower.

    I'm not disputing that the AF-C of the Sony A900 is not as good as a high end Canon or Nikon, but it does work on some subjects and is better than previous Sony DSLRs as far as I can tell (A100/A700 personally used).
    David Anderson

  16. #16
    Senior Member Braeside's Avatar
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    Re: Continuous AF on A900

    Shelby, tomorrow - weather permitting I have the chance to shoot some jousters on horseback, that should test the AF-C , I'll let you know. Probably be using the 70-400G or the 80-200HS G.
    David Anderson

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