One last 7D focus issue to tackle ...

I've had this camera since midway through basketball season last year. Have all focus issues put to rest except one and it's a biggie ...

While shooting football with Spot AF, the camera will STILL choose to focus on something closer to the lens than where there focus target clearly lands.

Why does this camera continue to focus on something that clearly isn't being targeted by its focusing technology? I'm clearly baffled by this and continue to get OOF shots when something (sports/football related) moves into the frame. Focus on target is dropped and the camera tells the lens to adjust focus on something that has moved into frame that is closer to the lens.

Here's a good example:

Looks to me like #17 is the closest player to you.

I presume you are using single shot focus rather than AI Servo then!

do you have AF point expansion 'on'? C.Fn III -6

if so, wondering if camera lost focus and one of the adjacent 'expansion' points picked it up again with 17 being on the newly focused 'expanded' point? pg.89 in the manual

You're in servo or one shot? If in servo, how do you have your focus priorities set in the custom functions? That could be a contributing factor.

Do you have C.Fn. III - 1 set to "Slow" (all the way to the left)?

Have you tried slowing the Al servo tracking sensitivity (C.Fn lll-l) to the slowest?That way you'll keep focus longer and it won't shift as fast to another target

Trying single point with expansion combined with C.Fn III-3-1 can sometimes help.
Hers's a series of images with Amanda running behind some bushes, deliberately dressed to be a difficult target, but the 7D is capable of tracking her surprisingly well anyway.
This is using Zone AF, to give the camera several AF points to keep on the target. Otherwise it has no chance, of course.

A few things that you didn't seem to mention in your original post:

1) 1-shot or AI Servo?
2) How your CnF is setup if you're on AI Servo. The tracking sensitivity (how fast it will jump to find focus again) can determine how fast the AF will lock onto some stray-objects coming into view.
3) I'm assuming you've MFA the lens at the specific focal length and no front/back focus issues?

Now all that is great assuming you can get focus lock on the subject you want initially... but seeing that it's such a cluttered scene... #57's hand/arm is in the center focal point... if you were trying to lock on #79 while the action was already going, then it would be pure luck to try and catch #79 in this scene (IMO).

can you post the exif data that might help us to help you Take a screen shot with the AF Point showing so we can see where it hits exactly

artyman wrote in post #11198108
I presume you are using single shot focus rather than AI Servo then!

Nosir. Always in AI Servo when shooting football. I've done this before!

dave

jb1911 wrote in post #11197960
Looks to me like #17 is the closest player to you.

Exactly. Closest and most in focus. The shot is the first example of one I could find where focus was dropped on the target and picked up with a target nearer the lens. #17 in this case.

dave

jwcdds wrote in post #11198439
A few things that you didn't seem to mention in your original post:

1) 1-shot or AI Servo?
2) How your CnF is setup if you're on AI Servo. The tracking sensitivity (how fast it will jump to find focus again) can determine how fast the AF will lock onto some stray-objects coming into view.
3) I'm assuming you've MFA the lens at the specific focal length and no front/back focus issues?

Now all that is great assuming you can get focus lock on the subject you want initially... but seeing that it's such a cluttered scene... #57's hand/arm is in the center focal point... if you were trying to lock on #79 while the action was already going, then it would be pure luck to try and catch #79 in this scene (IMO).

Answers:

1. AI Servo always when shooting sports

2. That CnF is set to the slowest setting so it's not supposed to jump around on me.

3. The lens has been MF adjusted at the 200mm end. It's the 70-200 f/2.8 L IS lens. It's at like +2 on the microadjust. The body is great and my lenses required almost no microadjustments at all.

Your last comment is a good one. I did focus on #79 before the play and tracked him because he was clearly out in space. Last game and I'm trying to get shots of kids who didn't play a lot this year, 79 being one of them.

I've seen a post here where someone has been able to recreate the 7D jumping focus from an intended target to something closer to the lens being introduced into the field of vision. This can sure ruin a shot!

dave

eddyav wrote in post #11198319
Have you tried slowing the Al servo tracking sensitivity (C.Fn lll-l) to the slowest?That way you'll keep focus longer and it won't shift as fast to another target

Good question and it's been all the way left (slowest) since original setup. Double checked and it's still there.

dave

mikemo618 wrote in post #11198300
You're in servo or one shot? If in servo, how do you have your focus priorities set in the custom functions? That could be a contributing factor.

Other than setting it to the slowest (to release a target) setting, what others should I be looking at?

Thanks!

dave