Canon 24-70 f/2.8 "L" lens... soft?

Eriktank

OK let me start by saying this lens is fast to focus, and QUIET. I love it for those two reasons out the door... I have a Tamron 17-50 F/2.8 and love it to death too, but it is NOISY and a bit slower on the focus...

My problem is - I've had three of these Canon L lenses that cost 1150, and each one has had a problem... first one was not focusing correctly - everything was in focus BEHIND the subject, by a margin of about 25%. So close-ups weren't noticable, but long distance shots were just terrible.

Second one had a mount problem and the camera didn't sense it was connected sometimes, other times it wouldn't fit on my camera, but when it did, it seemed to work better than the out of focus lens...

So on my third try (Thank you BHPhoto) I now have this stunningly sharp and awesome lens at 70mm. At anything wider than around 42mm, the thing gets so soft it's rediculous. It appears as though it might even be out of focus, but I did a tunnel test and no part of the surrounding tunnel was "sharp" - only the center was. Now if I shoot at f/5.6 or up - it's hardly noticable, but it IS still there (and very annoying). So basically I have a 50-70 f/2.8 since that's all it ever takes sharp pictures at...

I found on another forum over a month ago, when I had the problems with my first lens that people find this commonly with this particular lens... is this something that Canon can/will adjust to fix? Or is this just the quality crap of an L lens?

I have taken wide open test shots between the L and the Tamron and the Tamron beats the L in wide angle hands down... but the L lens kicks the crap out of it at 50mm. I'd say the tying point is at around 35-40mm probably. But the Tamron is sharp from center to edge, where the L is sharpest in center and fades soft quite badly at the edges unless you're above 50mm.

Can anyone point me in the right direction? It's been too long to return it to BHPhoto now... I was hoping with some practice I'd adjust to the L... but I've given it ample time and ruined a few photoshoots because of it... What's the point in spending 800 dollars more than the 28-75 tamron which obviously would have been better (at this point)?

Critics please?

ziggy53

It would be nice to see some sample images which demonstrate the difficulties you describe. 100% crops of center and corner or access to the full resolution original JPGs would be very helpfull.

I am interested in this "tunnel test"? I've not heard of such a test, so I wondering how it works and what it shows?

claudermilk

Sounds like a trip to Canon is in order. All I can say is my 24-70 does not have any of the problems I've read about--it's sharp all the way through the zoom range and aperture range.

Eriktank

Ziggy - a tunnel test is where you roll up a marked medium and put a focal point inside... a "good" tunnel test would be a posterboard with thick dark lines drawn on it every inch, and rolled up to about a foot in diameter - then hang something (tennisball) in the middle of the tube as the focal point. Centering the camera and using a wide open aperture will provide an accurate reading of the "edges" of the picture - judging by which lines are in focus on the rolled up medium. If your lens is showing a concave or convex focus (lines in front or beyond the focal point are in focus), I'm guessing that means it is out of alignment as well or is a defect in the glass, but mine doesn't show any focus on the lines on the sides - at least not as clearly focused and sharp as the tennis ball in the middle. Replacing the tennis ball with a sheet of graph paper also shows it fading out at the edges...

Claudermilk said what I was not hoping for, but expected - I'll have to send it to Canon next week after a few more important shoots are done. It still shines at 50-70mm at any aperture. Just wish I had a wide angle with it...