Canon tech notes re: AI Servo

[ziggy53]

I just stumbled upon this, written by Chuck Westfall:

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

ziggy53

[claudermilk]

Cool, I'll have to give it a read.

[wxwax]

When Sports illustrated sends half a dozen shooters to the Superbowl, I wonder if they'll be using AI Servo or manual focus?

[ziggy53]

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

[2whlrcr]

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?

[Jeffro]

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.

[claudermilk]

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

[ian408]

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.