Focus Problem

pearce_jj

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Evening all

Took the 5D with 135mm f/2.8 to the park with my two lads today. Looking through them, every single shot is OOF - the focus point is slightly in front of the subject.

Here's a 100% crop, the focus square was absolutely right on his eye yet it's got a few inches in front, so the chair is in focus instead.

http://sittingbourneSPAMerver.com/downloads/Photos/TP_Shared/focus_prob.JPG

And ideas?
 
The logical answer is that your 135 requires calibration.

A more remote possibility is that your mirror is dirty/fogged.

Bob
 
James,

It's a return to Canon/repair agent issue I'm afraid. It's worth trying it on another body first though.

There was some talk about the mirrors in 5D's having some residue that formed a bluish fog on them. Mine was not too clear when I got it and a gentle wipe with Eclipse fluid removed it. If the mirror is not clean then the AF sensors can get refracted light and the focus is thrown off.
Care must be taken if cleaning this as I believe the AF illumination squares can be damaged...I only discovered this afterwards but must have had a lucky day when I cleaned it.

Bob
 
Hi,

Just been using the test card and I've found that in AI Servo mode, which I use all the time, both the 135mm 2.8 and the 24-105mm F4L are significantly out (shot from the 135mm at http://sittingbourneSPAMerver.com/downloads/Photos/TP_Shared/test_card.JPG).

However 85mm F1.8 and 28-90mm cheapo kit zoom are fine ???

But in One Shot mode all is well, all lenses are spot on.

Camera problem them?
 
Have you got the expanded centre focus point selected....a custom function.

Bob
 
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