Sigma 18-300mm Focus Issue

Started 8 months ago | Questions thread
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tonyleatham New Member • Posts: 2
Sigma 18-300mm Focus Issue

I recently bought a brand new Sigma 18-300mm super zoom for when I travel with my Canon EOS 100d (I think it's called Rebel in the US).

I immediately took some pictures with it and was horrified by how out of focus the top of the image is. All the images were unusable.

I took several sets of comparison shots, using my 18-55 canon kit lens as a control.

The results were consistent: all Sigma images were out of focus in the upper quarter of the frame. All Canon images were in focus - same subject, same lighting conditions, same exposure settings.

I tried stopping the lens down massively - I saw an improvement but not enough to make good pictures.

The lens is now boxed, ready to be returned.

My question is: am I being too hasty? The 100d doesn't have AFMA, and even if it did, I'm not sure it would fix this problem as it's in focus at image centre, it's just the top that's miles off.

Is there something I can do to make things better?

This question has not been answered yet.
Canon EOS Rebel SL1 (EOS 100D)
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