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canon 55-250 IS blur edge, anyone?

Started Jan 15, 2009 | Discussions thread
maarensv
maarensv Senior Member • Posts: 1,106
Re: not an is problem

jrkliny wrote:

To test the optics, I recommend using a tripod with mirror
lockup and a cable release. You need to be sure that the camera has
a consistent focus. With my 450D, I would use liveview manual focus
with the 10x. To access edge sharpness, the objects at the center
and edges of the field of view need to be the same distance from the
camera. This is usually not possible. The more reasonable approach
is to shoot a flat scene.

I absolutely agree that the best test has not been done yet.

I've done some testing by taking pics of a flat object (take a poster or anything like it if you have no test chart), camera on a tripod with live-view manual focus for accurate focussing.

I do not agree that it can not be an IS problem. Test pictures with "my" 55-250 showed a sharp centre with very blurry corners. There was even a big difference in focal lenght, 55 and 250mm were fine, it was in between where the problems showed up. Replacing the IS solved the problem. The lens now works fine. It is optically far better than to be expected from such a cheap lense.

Sandor.

 maarensv's gear list:maarensv's gear list
Canon 6D Mark II Canon EOS R Olympus E-M5 III Canon EOS R7 Canon EF 100mm F2.8L Macro IS USM +22 more
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