Canon tech notes re: AI Servo

ziggy53ziggy53 Super Moderators Posts: 24,129 moderator
edited January 20, 2007 in Technique
I just stumbled upon this, written by Chuck Westfall:

http://photonotes.org/other/ai-servo.html

ziggy53
ziggy53
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Comments

  • claudermilkclaudermilk Registered Users Posts: 2,756 Major grins
    edited January 12, 2007
    Cool, I'll have to give it a read.
  • wxwaxwxwax Registered Users Posts: 15,471 Major grins
    edited January 13, 2007
    When Sports illustrated sends half a dozen shooters to the Superbowl, I wonder if they'll be using AI Servo or manual focus?
    Sid.
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  • ziggy53ziggy53 Super Moderators Posts: 24,129 moderator
    edited January 13, 2007
    wxwax wrote:
    When Sports illustrated sends half a dozen shooters to the Superbowl, I wonder if they'll be using AI Servo or manual focus?

    They used 11 shooters in 2004:

    http://www.robgalbraith.com/bins/multi_page.asp?cid=7-6453-6821


    I can't tell if there is an SI preference or not, regarding focus mode:

    http://www.siphoto.com/?canon1DM2N.inc
    http://www.siphoto.com/?canon1DM2.inc
    http://www.siphoto.com/?nikonD2X.inc

    It does look like they limit focus points.

    ziggy53
    ziggy53
    Moderator of the Cameras and Accessories forums
  • 2whlrcr2whlrcr Registered Users Posts: 306 Major grins
    edited January 17, 2007
    I have a Canon 30D and shoot primarily moto photography. My subjects are constantly speeding up, slowing down, changing directions. I thought AI Servo would be the prefered shooting choice.

    But after reading this, especially about the first shot typically being out of focus, I'm wondering if I should go back to the Single Shot mode. I rarely use the motor drive. I'm old school and tend to wait for the perfect shot vs. blasting off a bunch of exposures and then going back to choose the right frame. Even with my one shot approach, I thought AI would work with my moving subjects. Now I'm not too sure?
  • JeffroJeffro Registered Users Posts: 1,941 Major grins
    edited January 17, 2007
    2whlrcr wrote:
    I have a Canon 30D and shoot primarily moto photography. My subjects are constantly speeding up, slowing down, changing directions. I thought AI Servo would be the prefer shooting choice.

    But after reading this, especially about the first shot typically being out of focus, I'm wondering if I should go back to the Single Shot mode. I rarely use the motor drive. I'm old school and tend to wait for the perfect shot vs. blasting off a bunch of exposures and then going back to choose the right frame. Even with my one shot approach, I thought AI would work with my moving subjects. Now I'm not too sure?

    I have a 20D, and I'm not sure if the EOS-1 AI Servo is the same system as in the 20D or 30D, but I do know it works (center dot only) with motocross. I don't see the "first shot being out of focus" either. I imagine if you are nowhere near in focus when you start to track a subject you will miss focus...especially with fast subjects. If you are ready and prefocus on a spot, pick up your subject and shoot as you track you will have success. I have shot until the buffer is full with a bike doing the whoops right at me, with every shot in focus. That could not have been done manually....well not consistantly anyway.
    Always lurking, sometimes participating. :D
  • claudermilkclaudermilk Registered Users Posts: 2,756 Major grins
    edited January 18, 2007
    Since that appears to have been originally written in 1992, I expect a few advances to the system have occurred over the last 15 years. :D
  • ian408ian408 Administrators Posts: 21,938 moderator
    edited January 20, 2007
    Since that appears to have been originally written in 1992, I expect a few advances to the system have occurred over the last 15 years. :D

    That's true but the basic function and the document addresses that.

    Well worth a read too.
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