focus problems

I took hundreds of pictures at my sons soccer game and had several pics not turn out becuase the foucs was at the wrong point. I was shoot at 2.8 and used center point focus and automatic focus, but I can't tell a difference. I lost several great shots because they were OOF....

I realize that some of this may be user error, but I was wondering if you had some tips and suggestions....

below is a pic for example...... The focus should be on the players, but the Jonnie on the Spot is focused........

Suggestions?????????/

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What kind of percentages are we talking about, how many OOF?
This one is back focused pretty badly.

AF has a certain failure rate for several reasons.
Are you sure that your AF was focus locked on when you pulled the trigger?

I'll be honest, when I see this kind of backfocus issue it is almost always user error. The key is that I can usually find some items in the background that are in focus. What this means is that while tracking the action, the operator is allowing the AF sensor to wander just a bit off the subjects. The AF then grabs the background and you get massive backfocus.

As long as we are looking at this image....even if it was sharp this is not a keeper. You need to shoot with a much longer lens and crop in much, much tighter on the action. A good version of this shot would include the two kids around the ball and not much else....roughly 10% of the image you posted here.

I'm not saying it is not user error...

it is the full inage.......

How do I avoid "back focus"

I am not posting this as a keeper, but rather as an example........

I was shooting with a 70-200 at 2.8........ should I shoot at a higher aperature? Then I run into background problems (not being OOF)....

What is going on with the resolution/compression in that picture? It looks like a frame from a Youtube video.

Use AI Servo with center point only and make sure the center point stays on the subject when pressing the shutter button. With fast focusing lenses, getting off subject will cause the AF to shift to the background before taking the photo. I suspect you will improve with practice.

drmac wrote in post #5550862
I'm not saying it is not user error...

How do I avoid "back focus"
.

Select center AF point only and watch it very carefully to ensure it is always placed on an athelete.

You might also want to change C.fn.4 to relocate the AF function of the * button.

You can test this at home. Just walk toward a house & see if it's working.

iamaelephant wrote in post #5550989
What is going on with the resolution/compression in that picture? It looks like a frame from a Youtube video.

I had to reduce the quality a lot to get it to post...

JeffreyG wrote in post #5552470
Select center AF point only and watch it very carefully to ensure it is always placed on an athelete.

You might also want to change C.fn.4 to relocate the AF function of the * button.

I am sorry, but I don't know what this means........

CFn. 4 is a custom function you can set in camera. It will allow you to move the AF from the shutterbutton to the * button. So you seperate focus from exposure.
There's a very long thread about it here: Click