40D focusing issue (REVIVAL)

Guys, I know that this subject has been there for quite sometime now. I just called the Canon Service Center regarding this issue. The technicians asked which kind of lenses was I shooting it with. I told them that I shoot with an EF-S kit lens, a couple of EF lenses, a couple of EF "L" lenses, & have access to all "L" lenses. To sum it all up, I said I shoot mostly with "L" lenses!And was really shocked when they told me that the AF capability of the 40D is fully optimized ONLY for EF-S & EF lenses & NOT for "L" lenses! So, I panicked! My 70-200 2.8 L is tack sharp while my 24-70 2.8 L misfocuses at times eventhough the date code is UX...which is a 2009 production. I was adviced to bring the camera body so they can RE-PROGRAM the body to perform accurately with the "L" series lenses.


Is there any truth to this one? Should I send my 24-70 also for re-calibration? Please advice.


PS:


My 40D is with the current 1.1.1 firmware.

"L" lenses are "EF" lenses (just a high-end subset of them). What's likely happening is that one or more of your particular lens/body combinations needs calibration. Read the article, 'This lens is soft' and other myths.

Quote:

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Originally Posted by neuroanatomist

L" lenses are "EF" lenses (just a high-end subset of them). What's likely happening is that one or more of your particular lens/body combinations needs calibration. Read the article, 'This lens is soft' and other myths.

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Thanks for the link!

yep, that's almost certainly what's going on. Unfortunately the 40D doesn't have the micro-adjustment feature so we're kind of stuck; calibrate your most-used lens and take your chances with the rest of your kit, or compensate using MF. Obviously it'll depend on how bad your images are.


My 40D/50 1.4 combo is the only one that has an issue so I generally MF with this lens. As you'd expect it's not my first choice for action shots! But with practice I've gotten pretty good, pretty fast getting a sharp image.


I know many folks swear by the AF-S screen as a replacement for the original focusing screen in the 40D. My experience with it was a disappointment; in fact I notice no difference at all. Honestly I think somebody slipped the wrong screen in the box.


Anyway, if it comes to MF for you, give the AF-S screen a try. Most of the reviews of it are positive. It's only about $40 and if you buy it from B&H you can return it for a full refund if it doesn't perform the way you expect.


Best of luck!