Canon 20D - AF too slow?

I'm an amateur and I have had my Canon 20D for approx. 2 years now and have been very happy with it for the most part. I recently purchased a (used) 300mm 2.8L lens to photograph mainly motorsports, with the hope that it would help take me to the next level.

I went to Laguna Seca for the MotoGP race and I was totally disappointed in my results. At first I thought it was all user error, but I then went to the AMA races at Virginia International Raceway (VIR) and did some experimenting. While my results were much better. The pictures still were not a sharp as I expected them to be. I was able to use focus fixer to get some of them to where I thought they should have been coming out of the camera.

After both of these disappointing results, I thought maybe it was the used 300mm, but after reading the thread about the troubles w/ the new 1D MarkIII AF issues, I beginning to think it is the camera, since almost all of my issues are from fast moving objects coming towards or away from me.

My reason for posting is to get other peoples feedback as to the cause.

Not being a Pro camera, is it simply that the 20D AF system is not fast enough for what I want it to do? I'm considering upgrading to a 1D Mark IIN or Mark III, but being an amateur, I don't want to spend the money if I don't have to.

Or if other 20D users are happy with their AF on fast moving objects to and away from the camera, perhaps it is my 20D.

There is still the possiblity that it is all user error too.

Below are some shots I took as an experiment of my gf's dog. Shutter speed was set at 1,000. ISO 200 and wide apetures to concentrate on the focus points. I was using center point focus point and I put a green dot on the center of the picture. The last picture is to show a static shot to prove the camera and lens do work together.

Any help/advice/feedback would be extremely appreciated!

Which AF mode?

Keith R wrote in post #3970794
Which AF mode?

Good question - one would presume you're using AI Servo, but if you're using AI Focus that could be a contributing issue.

Mark

20D is NOT THAT BAD as your pictures show,,,
Just use servo mode in AF settings - you'll be fine.
I'm using 20D for two years now too and sometimes forget to switch AF mode.
Try to read manual - very helpfull!
100-400IS L lens I've used with it is not bad wide open to track moving objects, but F4.0 500IS is very good.
Your F2.8 300 is awesome lens and you don't need to upgrade your body, just plat with the same setup in different AF modes you'll have an astounishing results!
I'll never sell my 20D even I have bought 40D a week ago...

Mark_Cohran wrote in post #3970803
Good question - one would presume you're using AI Servo, but if you're using AI Focus that could be a contributing issue.

Mark

I'm actually assuming One Shot here, Mark!

I have used the 20D+Sigma 100-300mm f/4 combination several times and as long as you use AI Servo it usualy works. Not the best shot, but this shows a similar situation:

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Keith R wrote in post #3970794
Which AF mode?

Sorry folks, its in AI Servo. Continuous Shooting and Shutter Priority.

I wish it was something as simple as being in AI Focus.

Pilot1962, good to hear you don't think it is the 20D and you are getting good results, so perhaps it is just my 20D.

Also, just to add, I noticed while in Laguna that when pushing the shutter button, the lens would go way out of focus before trying to go into focus. This would obviously slow things down.

Lens was set to 6.4m to infinity too inorder to try to speed it up.

Thanks for the input guys. Please keep it coming as I am out of things to try.

--Mike1515

I cant say for sure whether or not your lens has a problem. but i would say in my experience the 300 is much more accurate on my MKIII than on the 20D, i use the lens on both cameras for different situations. Mine certainly has never been that bad though.

My 20d is also 2 years old, and I have really hammered it with sports! It seemed very slow and hard to focus the last time I shot boxing, even with the 50! Granted the building was dark. But I too wondered if it was getting senile on me.

WAS THIS SINGLE POINT OR ALL POINT's the first 2 are focused on the BG N03 is on the grass right hand corner,No4 looks like it never even tried to focus,No5 looks how it should be.
Rob.

Assuming you've got the camera setup as you indicated, then it looks like the lens may have a problem. One thing to check is to make sure that you don't have the lens's range limit switch set to exclude the distance to the subject. I don't have the 300 f/2.8, but I have the 200 f/1.8 and 400 f/2.8 and I can tell you that those lenses should lock into focus almost instantly. It should be the fastest focusing lens that you own, assuming you don't have other big whites. The 20D should be more than capable of tracking a steadily moving subject like you are talking about.

And just to cover everything you mentioned... the Mark III focus issues that you mentioned are on some bodies, not all. My Mark III has worked fine.

Thats something I was about to ask. If your letting the camera pick your AF point then you may be asking too much of it. Select centre point only.

I hate to say it, but I bet the problem is "I was using center point focus point and I put a green dot on the center of the picture."

I bet the center point was actually just to the side of the dog in these and you focused on the bushes in back..they are more in focus for the most part...the two where you kinda got focus you were probably on the dog but not quite focused yet...

How about trying CF4 and set the * button to do the focusing?

My 20D works okay with my 300 f2.8:-

One from Latvia a couple of months ago!

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Mike where are you in nc? Im in fayetteville and I have a 20 d. i can meet up with you try my body see if the same things happen. i will be at VIR for the GT Live event on oct. 6th &7th shooting pics for subie sport aswell if you wanna come up there.

Rob