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November 9, 2007
"Test Your Lenses When You Get Them"
With Rob's recent posts about photography in Peru with his new camera, this e-mail from Allen Jeter about Canon lenses should be of interest:
So I learned a really valuable lesson. I have done a lot of photography the last six months. With two lenses one a very expensive Canon EF 24-70mm 2.8L USM normal zoom lens that is supposed to be the mutts nuts cost me a little over a grand. And a rather inexpensive Canon EF 75-300mm USM III telephoto cost me under 200. Guess which one was taking consistently sharper photos. The el cheapo that the experts on the forums and review sites said was no good. I recently was going back through a lot of the photos I had taken and noticed this trend. The Canon L series is supposed to be the creme de la creme of Canon lenses tack sharp worth every penny etc..
Well it turns out my particular copy has an auto focus issue specifically a back focus issue. Essentially in auto focus it focuses to far back from the focus point. Check out the test shots at http://www.allenjeter.com/testshots. Apparently this is not all that uncommon with this particular lens and I have heard it happens with other lenses even other high end Canon L lenses. Apparently my copy is the minority most folks say they love this lens and it's the bestest etc.. and apparently they can calibrate it at the repair center and change it's focus point and it should be all better. So I have to send my main lens to Canon and be without it for a couple of weeks and hope that they do a good job and fix it right. Else I have a $1000.00 door stop.
But the thing that really sucks is I have been shooting with this lens for 6 months before I figured this out. I knew I had a lot of blurry shots but thought it was somehow me. Never would I have imagined it was my supposedly fantastic Canon L lens. I bet I missed at least 100 keepers because of this. And a lot of the shots I do have would likely have been more sharp if I didn't have a bum copy. So my advice is when you get a new lens test it under controlled conditions and don't assume it's good. For my test I shot under studio lights, on a tripod, with a cable release and using mirror lockup, Also I used some ISO test charts I got from here http://www.graphics.cornell.edu/~westin/misc/res-chart.html
Cheers, Allen
Posted by Robert Racansky on November 9, 2007 at 3:58 PM
Comments
This is getting old...
Posted by: SS on November 9, 2007 at 9:27 PM