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Old Feb 3, 2005, 12:47 PM   #21
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golfer, I did see your comment about the mag. I hope this change isn't "by design" or I will be really annoyed. First, they drop the RAW buffer size (but increase the write speed, so we can live with that.) If they actually made focus tracking worse intentionally I will be very annoyed. To put it mildy. Not that there is much I could do, except vote with my money... and I have too much spent to do that.

NHL, thanks for the clarification. that is how I remember the 10D working (the center for locking and all for tracking.) I must admit I haven't read as much of the 20D's manual as I have the 10D.

Like you, I wonder if the problem isn't partially the smaller AF points. That would mean that I could get better results by getting better myself. I'd like that.

What I don't get (I never saw the 10D do this) is that it seems to swich focus at the slightest hint of confusion. I remember the 10D seemed to stop tracking when the subject moved in front of a similar color subject. It didn't hop to the background instantly. Sure, it seemed to stop focusing, but at least it kept the same focus and easily locked back when the subject came out from in front of that subject.

I'm going to a photo sharing sesson with lots of good photographers. I'm hoping someone where has the 20D as well and we can talk about this. Maybe I'll learn something.

Eric
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Old Feb 4, 2005, 2:38 PM   #22
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NHL mentioned in another threadthat you need f2.8 or better to take advantage of the "high precision" center focusing point.
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Old Feb 4, 2005, 7:36 PM   #23
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:?Eric, the article I read was in the last pages of the mag. and it appeared as something they noticed about the camera. Wish I had read it more carefully. I may go by the bookstore and see if I can find it. [read it in the doctors office]

Iwonder if it is more like Canon was able to increase the read speed of the system, but overlooked a situation similar to what we are describing.

I'm like you, the 20d is going to be with me a while and I just wnat to learn as much as I can about its limitations. Without you guys, I probably would have thought it was just my bad picture taking etc. I guess, one aspect of photography is learning how to use your equipment.
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Old Feb 4, 2005, 9:37 PM   #24
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Golfer: was it this magazine Digital Camera Magazine? There are so many on the store shelves with almost the identical name it is tough to pick one out. :?The local Chapters/Indigo has the March issue now :sad:.
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Old Feb 4, 2005, 10:46 PM   #25
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Ewok,
Yes, I know that the high percision center AF point is only high percision at f2.8. That is the same as the 10D (that I had before.) I wish it worked that way at f4... but to get that you need a 1 series camera (their "Pro" bodies) and I know the 20D isn't one of those.

It would be nice, but I know that Canon uses that to differenciate between their amature & pro bodies. I doubt it will ever happen.

It still should have been able to do it. I believe the 10D could have tracked them, so I think the 20D should have been able to.

Eric
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Old Feb 8, 2005, 8:54 PM   #26
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:? Peter; sorry I have not gotten back to you. I have not been able to get to the book store. Your title looks right, but without seeing the last page I can't be certain. I know it was the last article of the mag. If I find it, I will be sure to let you know.
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Old Feb 15, 2005, 8:05 PM   #27
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I realize this is an old thread, but I just wanted to show an example of what happened to me this weekend.
http://esmith.marx7.org/web_posts/20D-tracking1.jpg
http://esmith.marx7.org/web_posts/20D-tracking2.jpg
http://esmith.marx7.org/web_posts/20D-tracking3.jpg
http://esmith.marx7.org/web_posts/20D-tracking4.jpg

Notice how the 3rd picture has the background very nicely in focus? This wasn't a money shot, I was just practicing focus tracking. But it still really annoyed me.

Eric
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Old Feb 16, 2005, 4:31 PM   #28
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Eric - I read your original posts in this thread and wondered what was going on. I wonder if the F2.8 AF limit of the 20D is causing your problem.

I have a test similar to the one suggested by NHL that you could try. The goal would be to duplicate your situation with a lens that is F2.8 or faster and see if the problem still exists.

Take your longest lense that has at least a F2.8 aperture and try panning with birds in flight like you do for the owl shots. Maybe you have a 135mmF2 or a 200mmF2.8 that you could try. Find an old church or maybe a post office where there are lots of pigeons or other small birds. Hopefully they will be the same relative size in your 200mm lens as the larger birds are in your 600mm lens.

Try panning with the small birds and see if the focus jumps to the background. Try both the center focusing point active and the automatic focusing points.

This is just a thought. I know it's bugging you, maybe it will shed some light on the problem...


-jb
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Old Feb 16, 2005, 9:40 PM   #29
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Unfortunately my only f2.8 lens or better is the 50mm f1.8. But I bet that would still work on gulls or something. An interesting idea, I'll give it a try.

Eric
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Old Feb 17, 2005, 6:20 PM   #30
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Just remember the minute you drift off the bird - yer dead. AF doesn't know where to go. Kinda tricky with small/fast birds.

Thats an 80MPH road track car in my avatar, coming around a sweeping curve. Geometery goes to hell - so I shoot some nice grassy areas sometimes.
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