Original 17-85 IS Tests Photo Gallery by Ingo Rautenberg at pbase.com

Original 17-85 IS Tests

Various focus tests with the original 17-85 IS lens bundled with my Canon 20D and which turned out to be a bad copy. The center focus point would consistently result in 1" backfocus or more. Even when shooting macro subjects. Same issue when normal multiple focus point setting used. The second copy was and is "spot-on." One reason I prefer to spend the extra $ when buying a camera and lens at your local brick and mortar store.

IMG_0295_fp.jpg	IMG_0295 Closeup	IMG_0294.jpg	IMG_0294 Closeup
IMG_0302_FP.JPG	IMG_0302.JPG Crop	IMG_0303_FP.JPG	IMG_0303.JPG Crop
IMG_0304_FP.JPG	IMG_0304.JPG Crop	IMG_0305_MF.JPG	IMG_0305.JPG Crop
IMG_0331_FP.JPG	IMG_0331_crop.jpg	IMG_0332_FP.JPG	IMG_0332_crop.jpg
IMG_0333_MF.JPG	IMG_0333_crop.jpg	IMG_0362.JPG Center Focus crop	IMG_0363.JPG Top Focus Crop
IMG_0364.JPG Adjusted Center Focus Crop	IMG_0400_web.jpg	IMG_0400.JPG Focus Point	IMG_0401_web.jpg
IMG_0401.JPG Focus point

comment |

Ingo Rautenberg		30-Jun-2008 22:49
The way this chart is set up is that on focuses on the center line of the "box", which will line up with the line behind it on the paper and the line with the arrows at the bottom of the "box" indicating the desired 45 degree angle has been achieved. I assure you did this test properly.

Guest		15-Mar-2008 11:04
Have you done the test correctly? Did I miss something or understood? :-/ If i understood the idea of using this focus chart, you should place the lines match together when you are focusing on the center of the paper (the black line on the paper in front of the box) not on the line on the box. You can do it easily placing the paper and the box on a door, then focusing your camera on the line of the paper and moving the door front or back getting the lines (from the paper and the box) match together. Then you have a perfect 45 degree angle and you can read the result from the paper if you have front or back focus. That is what I understood and the way I have tested my all objective.

Ingo Rautenberg		05-Dec-2006 04:33
Peter, I appreciate the comment, but that would be true IF I had the camera set up at a 45 degree angle and without the "box," which is actually only half a box. If you can read the writing, the way the paper triangle is set up, focus should be on the line in the middle of the box, which is on the same plane as the lineswhere the "box" meets the paper.

Peter		21-Aug-2006 09:30
Considering the test chart photos, it looks like you have focussed at the middle of the box. For the tests to be usefull, you should focus on the "focus line" in the middle of the paper sheet.

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