Sigma 35mm 1.4 beware of focus issues close to infinity

Started 10 months ago | Discussions thread
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Daniel
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Sigma 35mm 1.4 beware of focus issues close to infinity
10 months ago

When I received my Sigma 35mm F1.4 Arts lens, I was impressed with the optics after I fixed the front focusing with MFA setting of +13.  However, after a couple months of use, I noticed my landscape images weren't as sharp as when I was shooting people.  When my Sigma USB Lens Dock arrived, I played with fine tuning my lens for hours.  Now, I noticed there is something wrong/defective with the far end focus from 2m to infinity.  At 2m end, MFA setting of +13 is needed but at infinity end, MFA setting of +7 is needed.  Because 2m to infinity are in the same MFA section for this lens (using Sigma USB lens dock), I can only fix either 2m side or infinity side but not both.  Worse yet, I noticed that the focus is not consistent, especially worse toward the infinity end.  If I set my Canon 5D Mark III to AI Focus mode and try to focus on a stationary high contrast object close to the infinity end, focus will hunt non-stop. This problem still exist near the 2m end but not as bad.  Everything else from 0.3m to 2m is working fine with consistent focus after applying MFA.

Anyone else noticed focus problems from 2m to infinity?

1.  2m and near infinity focus need different MFA settings.

2.  Focus is not consistent, hunts in AI Focus mode more so near the infinity end.

Daniel

Canon EOS 5D Mark III
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