First, like everything made at times there will be a dud. Canon cameras and lens are no exception.
I got a DOA EF 135mm f/2.8 Soft Focus once. First click of the shutter and the aperture blades stuck shut. I returned it; no big deal.
I agree with you. I went through the process you described when I
got my 300D - it tooks months to get used to it. However, the 20D I
have didn't work as well (with my 24-70L and 70-200 f4L) - Canon
fixed it and it now works very well. So, how is this explained? How
come I see similar problems and they are dismissed as user error?
They are dismissed as user errors because so often that is exactly what they are. How often do we see post here from somebody complaining about "soft images" that if they actually post the image and EXIF data you find the shutter speed is very low and they are handholding. Well DUH you need to up your shutter speed it wasn't the cameras fault. How often do we see the post about my camera back focus. They show an image of a subject with a bush, fence, brick wall, you name the high contrast object behind the subject that is tack sharp. Well yeah the cameras focus sensor picked up the high contrast subject. We see focus test in low light where the focus clearly is within the depth of focus when viewed at normal size. Of course the image is at 100% and the focus wasn't dead in the middle or better the1/3 back and the person is complaining about focus error. We'll Canon's specs call for within 1 depth of focus with the 1.6 bodies. So the camera is preforming as advertised.
A while ago a guy posted a picture of a rabbit silhouette in a weedy spot surrounded by a chain-link fence. Lens used was a 70-200f/2.8 at f/8 focal length 200mm shutter speed handheld was 1/60 sec. Nothing in the image was sharp...motion blur big time. He is complaining about a focus problem. He been shooting for 30 years and worked as a photographer for a newspaper. His opinion was the 20D was junk. Golly my opinion was he didn't have clue. It wasn't the camera it was the shaky person holding it. Other images posted the focus was where he said it should be but they all showed motion blur... DUH! So yes often the problem is the user.
IMHO, people experienced with a DSLR who think that have a
problem should do two things:
I think you missed the first thing to do.
Rule out and or eliminate possible technique problems. Be honest with yourself. Then get a good high contrast target. Drop the camera and lens on a good tripod (been at this a long time...notice good tripod...some tripods and heads aren't much better than handholding...but that is for another thread) mirror lockup, timer and shutter release. Make sure the distance is reasonable. Take a bunch of photos. OK..key here.. open them up or print them at 8x12 inches this is the size Canon uses to judge focus and is in the specs. Look at it at reasonable distance. Next you are going to need to know the depth of field distance. Did it focus within the DOF? Notice I didn't say in the middle or 1/3 back. If it isn't ( and it isn't focused on the grass, stick, fence or brick wall behind the target) you could have problem. If you do then send it to Canon. From what I have seen here often even if it is within spec they may tighten things up a bit and make it even better.
1) Do not post a description of the problem here because it won't
help.
2) Send the camera to Canon for calibration.
--
Bill
Taking It One Day At a Time
http://www.pbase.com/slowpokebill
'The fact that no one understands you doesn't mean you're an artist.' Unknown
'Every man dies; but, not every man lives' Braveheart
'Sometime the magic works. Sometimes it doesn't' Little Big Man
