Backfocusing

I shoot a lot of college volleyball and basketball games and have been frustrated by backfocusing no matter what camera or lens I use. I'm starting to wonder if the "problem" is that I'm too picky about focusing, or if it's operator error of some kind.

The problem has occurred throughout my use of the 20D, 40D, 7D and the 85mm, 100mm and 70-200mm lenses (Canon all) over the last five years.

I set the focusing mode to AI Servo and use the center point only. My aperture is 2.8 and I usually let the camera pick the shutter speed.

I switch to One Shot mode when I shoot someone at the free throw line, but those often turn out softly focused, too.

So what is my problem? Am I too picky? Or am I doing something wrong?

It might help if you dropped a few Images in the thread for us to look at..

Ralpho wrote in post #11603113
I shoot a lot of college volleyball and basketball games and have been frustrated by backfocusing no matter what camera or lens I use. I'm starting to wonder if the "problem" is that I'm too picky about focusing, or if it's operator error of some kind.

The problem has occurred throughout my use of the 20D, 40D, 7D and the 85mm, 100mm and 70-200mm lenses (Canon all) over the last five years.

I set the focusing mode to AI Servo and use the center point only. My aperture is 2.8 and I usually let the camera pick the shutter speed.

I switch to One Shot mode when I shoot someone at the free throw line, but those often turn out softly focused, too.

So what is my problem? Am I too picky? Or am I doing something wrong?

Well, if it's happening with multiple cameras and multiple lenses over a period of time, it's pretty unlikely that all the cameras AND lenses are at fault so that essentially eliminates your gear and leaves only one thing...

As TTk said, post some images so we can see what's going on.

Here are two from a game I shot yesterday.

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They're pretty small and not that sharp, but it looks like the focus is on the rearmost player in each shot. Does that match your observations?

I assume this is with the 7D? Post the relevant C.fn settings.

Ralpho:

Here's a nearly identical shot to your first with the three players. I focused on the guy in white jersey handling the ball with an 85mm f/1.8 lens on a 7D:

I feel your frustration and you would think 2.8 would give you a little more room for
margin of error. I shot with a friends 7D yesterday and was pretty impressed with it.
I have a 1DmkIII so I was not familiar with the menus but tried to set it up on the fly.
I could not find the setting to use just one focus point ( center ) so the camera was picking
various points and perform pretty well. I also did not want to switch it to back button (*) for
focus as the camera owner it new with the cam. With my 100 f/2.0, I usaully just shoot wide open.
I'm sure you tried all this kind of stufff including micro focus adjustment.....

Joemt.

2.8 giving room for margin of error? I don't think so. It's a necessity for low light with no safety cushion IMO for actively (and erratically) moving targets.

AntonLargiader wrote in post #11603300
They're pretty small and not that sharp, but it looks like the focus is on the rearmost player in each shot. Does that match your observations?

I assume this is with the 7D? Post the relevant C.fn settings.

Yeah, I shot these with the 7D. I'm not using any relevant custom functions. Shooting RAW, too, if that makes a difference.

snyderman wrote in post #11603324
Ralpho:

Here's a nearly identical shot to your first with the three players. I focused on the guy in white jersey handling the ball with an 85mm f/1.8 lens on a 7D:

for comparative purpose, I have the 7d setup like this: AI Servo, highspeed shooting; Spot AF (the one that looks like [.] ), no other focus points available. Std settings are f/2, 1/640 at ISO 2500.

Shows it IS definitely possible to be shooting at nearly identical targets and get the focus assigned to the correct player with a 7D.

dave

I get an occasional shot like yours, where the focus is exactly where I want it to be, but focus is off (almost always too deep) nine times out of ten.

Ralpho:

If it was just your 7D, I'd say it most definitely had a problem and maybe a trip to Canon Repair Service might help. The fact that you said the issue is constistent among bodies and lenes kind of puts the issue squarely on you and not the equipment. Is this your understanding as well and you're just trying to find out why?

dave

2.8 with a camara capable of very high ISO ( and still useable ) would certainly increase your
depth of field over the razor thin 1.8/2.0. I thought it was a smart move by the original poster
to try to increase the DOF in an attempt to get better focus. This still has not solved the problem
however.

Joemt.

I think part of the issue you are having is it looks like really high iso to me.

snyderman wrote in post #11604358
Ralpho:

If it was just your 7D, I'd say it most definitely had a problem and maybe a trip to Canon Repair Service might help. The fact that you said the issue is constistent among bodies and lenes kind of puts the issue squarely on you and not the equipment. Is this your understanding as well and you're just trying to find out why?

dave

Yeah, I understand that my problem is not faulty equipment or a need to microadjust for a certain lens. Either my expectations for getting sharp focus during an indoor basketball game without using flash are too high, or I'm doing something wrong.

I thought the denizens of this forum might know something I haven't thought about.

I was using iso 3200 on the game yesterday, but usually use 1600 and get the same results.

And here's another picture, by the way.

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Joemt wrote in post #11604436
2.8 with a camara capable of very high ISO ( and still useable ) would certainly increase your
depth of field over the razor thin 1.8/2.0. I thought it was a smart move by the original poster
to try to increase the DOF in an attempt to get better focus....

Sure it's better than 1.8, but it's still not very forgiving. BTW assuming it was shot with the 70-200, it's not really increasing the DOF to shoot at 2.8 since that is as wide as the lens will go. Maybe try 6400 at f/4.

As far as the C.Fns go, he might not think he has set any applicable ones but the camera is certainly using the AF-specific settings that are there now. It may be interesting to see what they are. Specifically the first three:
C.Fn III-1 AI servo track sensitivity
C.Fn III-2 AI servo 1st/2nd image priority
C.Fn III-3 AI servo track method