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Old Nov 18, 2006, 6:08 PM   #1
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The attached photos were taken with a 20D in a continuous burst...focus is poor in the first and better in the second and third. I was shooting manual shutter speed (400th) and aperture (2. to help speed up focus at ISO 3200 with AI Servo focus using a Canon 550 flash set for high speed sync with a canon 75-200mm 2.8 lens.

I see this frequently where a single shot or the first photo in a burst is out of focus even with the single center docus point on the subject of interest. Any ideas on what might be the problem and how I can get better yield. By the way I use a monopod.

Apparently, in order to see all 3 photos I have to send three messages
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Old Nov 18, 2006, 6:09 PM   #2
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here is the second photo
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Old Nov 18, 2006, 6:11 PM   #3
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here is the third photo
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Old Nov 18, 2006, 6:26 PM   #4
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coachjerry

Now that I see what you're trying to figure out, I think you'd probably have better luck asking for advise in our Canon dSLR Forum

The members there are going to be more familiar with any "qurks" associated with the available Autofocus modes and can give you some tips.

So, I moved this thread there so that they'll see it.

An observation... The first photo is indeed backfocused (focusing behind your subjects). This could be related to the AF mode you chose. Hopefully, some Canon shooters will comment on the best way to shoot sports with your camera.

Another observation.... You're shooting at ISO 3200 with flash. Flash exposure tends to be relatively inconsistent with most models at ISO 3200. I also see blown highlights in these images. So, you may want to see what kind of shutter speeds you're getting without a flash. The results may be more appealing.


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Old Nov 18, 2006, 6:29 PM   #5
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Thanks JimC
This is the first time I've posted a photo and I wasn't really sure where or how to do it.
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Old Nov 18, 2006, 6:31 PM   #6
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I added a couple of comments to my first post, too (I didn't edit it quite fast enough, though). lol

There are several members here that shoot sports with a 20D or 30D. So, hopefully, they'll see this thread and offer some tips.

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Old Nov 18, 2006, 10:48 PM   #7
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This is typical of AI-Servo AF

This subject has been discussed many times before:
1. The camera is in shutter priority in AI-Servo and will release before focus can be achieved on the 1st shot if the shutter is released quickly, the camera will then try to track the subject in subsequent shot provided it can lock otherwise the frame rate will be maintained @ the expense of the AF
2. In contrast with One-shot AF the camera will only release if the AF is locked otherwise the shutter won't fire...


BTW if you're using the 550EX in High-Speed Sync mode, you might as well turn the flash off because it's not contributing anything to the image! :idea:
-> HSS severely cut down on the distance and from the look of your posted images the subjects are just too far away for it to do any good
Plus looking from the casted shadows on the subjects the light is coming from a different direction from your flash anyway (which is not contributing to the lighting at all).
All illumination is from above and from the right - I would remove the 550EX to keep the camera lighter (and stop wasting the battery)... :-)
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Old Nov 19, 2006, 6:55 AM   #8
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Jerry,

Welcome.

NHL pretty much hit the high points on AI-Servo. The key is you need to lock focus and track BEFORE firing that first shot off. I always use AI-Servo and following this method I don't have the OOF first shot problem in 95% of my first shots anymore. Once you understand the first shot is shutter priority you just have to adjust your approach so you acquire and give focus the half-second needed to achieve focus. Note: one-shot doesn't achieve focus any faster it simply won't allow you to fire until focus is achieved. For this sport, you are doing the right thing by staying in AI-Servo.

As to flash in HS synch - it's still usefull as a fill flash for illuminating faces - really the intended purpose of the flash in this situation. So, I recommend you still use it. But 25 yards is about the max distance in HS synch.

Good luck on your next outing!
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Old Nov 19, 2006, 8:39 AM   #9
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One thing I did forget to mention. I'm not sure if it was your flash or post processing, but your highlights look a bit blown out. It's a bit stark, so you'll want to tone it down a little
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Old Nov 19, 2006, 10:21 AM   #10
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Thanks NFL and JohnG
I wasn't aware of the fact that the first shot is with shutter priority in AI Servo. To work with AI and get the first shot in focus I assume I should push the shutter release button halfway down and wait until focus is achieved then take the shot.

NFL--Regarding the flash, sometimes it is on and sometimes not--I have been experimenting with this. I have shot football at night without it but am of the opinion there has been some help on shorter range shots. Also I beleive I get better results if I shoot at speeds greater than 1/250--which is why I sometimes use hi speed sync on the flash. By the way all the football games I cover are at night and some high school field lighting is better than others.

JohnG--I don't recall whether thesee three shots were post processed or not. I will pay attention to the hhighlight aspect when I shoot the next football game on Friday night.

Do you guys agree that in the relatively "unchanging" lighting conditions at night that shooting manual shutter and aperture is of value in speeding up auto focus...in the same subject, are either of you aware that the 30D offers a significant advantage in the speed of auto focus?

Thanks to both of you for your keen observations.
Caochjerry
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