17-40f/4 calibration

[edmund]

I have a 17-40, and I've been a little suspicious about its sharpness .... 'cos it doesn't seem as sharp as other users describe. it's kind of OK, but that's all. Hmmmm. I bought the lens in the US - but now I'm in a remote part of Norway - so I can't just drop it off at a Canon service center and get it checked. Is it possible to do do-it-yourself calibration? If yes, how?

[RichardtheSane]

I doubt 'DIY calibration' is possible

Do you use a filter?

[edmund]

Yes - a 'Canon UV Haze'. Hadn't thought of that.... I'll take it off in the morning and try a couple of tests. Thanks for the idea.
Anybody else have any thoughts?
Anybody else sent their 17-40 in for calibration and seen a big difference on its return?

[RogCincy]

Yes - a 'Canon UV Haze'. Hadn't thought of that.... I'll take it off in the morning and try a couple of tests. Thanks for the idea.
Anybody else have any thoughts?
Anybody else sent their 17-40 in for calibration and seen a big difference on its return?

I think your haze filter could be a problem. You want to cover the lens just with a UV filter unless there is a reason for the UV haze.