Large double onion ring in the middle of shoots when i useing Sigma 35mm f1.4 DG HSM Art lens on my Canon 6D mark ii

Question

I've bought a Sigma 35mm f1.4 DG HSM Art lens, its works well on my APS-C Camara, but not work with My Canon 6D Mark ii (Large double onion ring in the middle of shoots), is this lens meant to work on both? Please let me know.

Thanks

Answer 1

Yes, DG lens serie from Sigma are compatible with fullframe cameras. About the effect seems like you enable in-camera lens correction. And this correct do not work well with 3th party lenses. Check page 200 of the manual of camera and switch off this correction

Answer 2

This is a known issue when using certain third party lenses with certain Canon cameras that have in camera lens correction enabled. It seems almost totally random which camera and lens combinations demonstrate the issue and which ones do not. As Roger Cicala says in the linked blog entry, some lenses work with some cameras but not others. At the same time other cameras that do work with those lenses do not work with other lenses that work fine on the cameras that have trouble with some lenses. There's a fairly detailed chart that shows which camera + lens combinations demonstrated the issue when they tested them with several different bodies, including one model with two different firmware versions installed. Unfortunately, the Sigma 35mm f/1.4 ART was not one of the lenses Roger tested because lensrentals did not stock it at the time he did the testing back in 2012.

Not only Sigma lenses but also some Tamron and some Tokina lenses experience the same issue. Perhaps there are other third party brand lenses that also do it, but those three brands are all that Roger tested. The issue seems to be that when the camera does not have correction information stored for a particular lens it knows to disable it when Canon lenses are mounted but does not always know to disable it when third party lenses are mounted.

Canon's recommendation is to turn off in-camera lens correction with these lenses. Pretty much everyone who has discussed it in online forums reports that the issue is not present when lens correction is turned off in the camera's menu.

Sigma has issued firmware updates for some of their lenses which they claim fixes the problem. If you have a Sigma USB dock for your Canon mount lens, you should check and see if your lens is running the latest firmware release. Version 2.00 released on June 12, 2018 is the earliest one that included the fix for your lens.