Calibrating Camera/Lens

[EOS_JD]

So I've had my camera and lens for some time and have been elighted with the quality but I noticed something the other day when shooting at the lenses closest focusing.

40D with a 24-105f4L IS.

Using the combo above, the cameras centre focus point doesn't seem quite as sharp as the outer points yet with other lenses it seems fine!

How can I get this checked? As I say it seems to be only the cetre point AF with my 40D and 24-105 but it's really tough to tell looking at other lenses - just more pronounced with the 24-105!

Anyone any ideas how I get this checked and how much it might cost?

Centre point (shot of the 10-22 f3.5-4.5 )

Far right point

THanks
Jim

 

[Hodders]

Are you focusing and recomposing when using the outside focus point ?

If so then at the short range you are shooting at the focal plane shift will be significant.

You may find that the lens is simply front/rear focusing a smidge. Try following one of the many guides on micro adjusting your lens.

Sorry that is all I can think of...

 

[EOS_JD]

40D doesn't have microadjustment. I do need to recompose with the outside point but that only makes it sharper - All the outside points are sharper than the center one!

 

[trencheel303]

this is a similar headscratcher to the autofocus system of my 450D, sometimes it back focussed, sometimes not, sometimes different points had different results, i gave up trying to fathom it and taught myself how to manual focus... I know its hardly a solution, as such, but i'm easily pleased and it works that way, obviously no good for action shots, but as long as you don't do action you're fine with MF. The autofocus system isn't 100% perfect in all situations and I do believe this is actually documented.

 

[EOS_JD]

Focus recompose for me then - Seems to work well despite me always advising against it