weird Sigma 12-24 f4.5-5.6 DG behavior with 7d and other bodies , help

Started Jan 20, 2013 | Discussions thread
mantra
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Re: weird Sigma 12-24 f4.5-5.6 DG behavior with 7d and other bodies , help
In reply to ronzie, Jan 21, 2013

ronzie wrote:

For testing focusing it is best to use a flat object like a newspaper page or other target with a large enough lettering to focus on. Try to get it in constant light and make sure the target is square to the camera, that is flat to the basically back of the camera (refrence image plane).


Hi Ronzie

i used a flat building  perpendicular to my camera , tripod , mirror lock up and remote shutter

even the center is more a lot more soft then my 17-40L or 16-35L

the corners are  unwatchable

i uploaded some photos on my gallery here in digital review

i will upload soon as i can the photos of the flat target

thanks

Ronzie

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