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Old Mar 14, 2006, 3:13 PM   #1
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Need advice on shooting Track and Field with 20D.

I am going to be shooting a track and field competition soon and want to know if anyone has any tips or trick I should try.

I have my Canon 20D and the following lens

50mm 1.8

18-55mm

70-300mm
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Old Mar 14, 2006, 3:49 PM   #2
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I haven't done it but you should try AI servo mode, shoot in burst mode. I would use longer lens to get more frame filling shots. Keep ss high bump ISO to 400 if you need to.

BTW - the camera is 20D not D20.
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Old Mar 14, 2006, 10:17 PM   #3
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AI Servo mode is what you're looking for. I believe it locks focus on the subject on the center focus point, and tracks the subject's movement with the other focus points. It also continually adjusts focus if the subject moves to or from the camera.

And if you have the new 70-300IS, keep the IS in Mode 2 for panning...

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Old Mar 15, 2006, 5:48 AM   #4
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Well I don't shoot Track and Field, however I learned a thing or two about how the AF works from my experiences with shooting birds in flight - I have a much higher success rate with One-shot AF than any of the AI servo modes, and here's why:

1. Single-shot AF put the camera in focus-priority, i.e. the camera will not release the shutter until the subject is in focus - so something will always be in focus depending on where the AF sensor(s) hit (or one does not have a shot) -> This mode is always deterministic based on an AF sensor!

2. AI-servo put the camera in shutter release-priority instead, i.e. the camera will release the shutter even before focus is achieved (especially the 1st frame). Subsequent frames will be in focus-priority BUT, and this is a big BUT there's a fixed time-out period (depending on USM/non-USM lenses) where the camera will give up focus to maintain the high frame rate (250ms for 5 fps) on the 20D for example -> if a subject moves a lot on long lens in actions and focus can not be achieved within this fixed time-out window the images are taken regardless. Secondly the camera predicts where the subject is depending on several sensors -> One can end up with a picture where none of the AF sensors are in focus because the camera predicted something in between! :evil:


Check it out: shut yourself in a dark closet, the camera will fire away regardless of the focusing in AI-servo...
-> Not so in One-shot AF, the subject has to be in focus for the camera to fire! :idea:
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Old Mar 15, 2006, 5:22 PM   #5
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I agree with NHL 100% here, I've tried AI servo for action sports and maybe one out of 10 shots will be in focus, at least the subject you wanted to be in focus. you are much better off using single shot.And also set you auto focus point to center point. I don't know much about using IS since I don't have a lenswithIS, but if you check out the sidelines of any pro sport all the photographers have a piece of gaffers tape over the IS switch holding it in the off position. They do use itfor a few shots, but most of thetime it is turned off.
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Old Mar 16, 2006, 7:47 AM   #6
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Here's an example of a One-shot AF capture:






-> This little guy is literary quite fast and does not follow a pre-defined 'Track' or the confined of a playing 'Field'. It moves by zig zaging in 3 dimensions. In theory AI-servo should work; However, in practice unlike the trained eye, AI-servo can not tell the background from the foreground moving so it'll predict something in between (or mostly the backround because there are more AF sensors hitting it)...
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Old Mar 16, 2006, 8:24 AM   #7
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NHL

You say more AF points hitting the background. Are you using point or multi point focusing?
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Old Mar 16, 2006, 10:19 AM   #8
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NHL and others,

While I understand and agree with what you are saying, I'm not sure the limitations of AI Servo will apply in this instance - i.e. track and field. You don't have eratic movement - you have very predictable movement. And, you also don't have the problem of a small bird - you should be close enough that your subject easily covers your focal point(s). And you will likely be in good lighting which is easier to obtain a focus lock. So, for this particularscenario I think the servo will function as designed and you'll get better results with it than with one shot. And, don't forget, some shots - hurdles and high jump are two where you can and probably should be pre-focusing rather than tracking - so your shot timing is more important than tracking your target. If your timing is right, the focus will be perfect. If your timing is off it really doesn't matter because you wont get the shot you need anyway. Just my take.

Now, the single focus point vs. multi focus point - this is still up for debate. I've heard from both camps on which is better. Some swear by one point some use all. I would say - for shooting track a lot would depend on your style. If you are using a long lens (say 300mm) at 2.8 you'll have a very shallow DOF, so you may need the accuracy of single point. If you're shooting at narrow apertures you likely won't have an issue with the camera selecting the wrong body part to focus on. And if you have multiple runners in a shot several feet in front/behind one another you may want to select which you are tracking.

So, my advice is to try both single and multi point and see what works for you. But I think the Servo will serve you better than 1-shot in this instance.
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