I just bought a 6dmk2, tried it together with my Sigma 50mm 1,4 DG HSM. it worked fine until i tried everything below F2,o gives a strange haloeffect in the preview.. even the previews when importing to loghtroom shows the effect, but when editing the photos after they been imported the effect is not visible anymore and the photo is fully normal. Never heard or seen this before, does anyone know what this is (see photos)