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Sigma 70mm Macro problem focusing

Started Mar 14, 2020 | Questions thread
Batzorig
OP Batzorig Regular Member • Posts: 135
Re: Sigma 70mm Macro problem focusing

I am sorry for slow response to your comment. I checked my before and after the accident shots and couldn’t really find consistent results showing the faulty focus on left corner. So, I am concluding that I may have overreacted to my last shots which showed some focus issue. And the issue might have been caused by my inability to align the artwork to the camera sensor, not because of the lens. After re-inspecting the shots, I realized that the back support of the artwork was a flexible PVC panel that bent a little when placed against the wall. The bending was slight enough that I didn’t really think it would cause a problem at that moment, especially when shot at f8 aperture.

Here is the image of the artwork I am talking about. It is a traditional style painting on silk. As you can see from 100% crops, the bottom left corner is a lot less sharp than other three corners. You can look at the pencil lines.

I am sorry for causing a false alarm about the lens performance. At the same time, Thank you for reminding me recheck the before and after shots. That was a smart advice!

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Bat

Example image. Shot in portrait mode and rotated clockwise.

Bottom Left corner @ 100% magnification. The out of focus corner.

Bottom Right corner

Top Left corner

Top Right corner

 Batzorig's gear list:Batzorig's gear list
Canon EOS 5D Mark II Canon EOS 5DS R Canon EF 50mm F1.8 II Canon EF 70-200mm F4L USM Sigma 70mm F2.8 EX DG Macro +3 more
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