Hi EF 50 1.2 L users,
I am a photography teacher, in a school for adults, and yesterday a strange effect occured on a lens of one of my students, an efect for which I can't find a reasonable explanation. The 50mm lens was used in studio, on a 90% white subject and produced varying white balances or color shades on shots taken immediatly after each other.
I tried different shutterspeeds, apertures, white balances, thinking there was something wrong with the camera sensor.
Then I tried different bodies, being 2 7D', a 450D and a 1DS, and always the problem occured. A heavy color shade, going from green to blue, more intense when working on full aperture, but still visible on f:8 and f:11
Has anybody seen this effect before, and more important: Has anybody got an idea of the reason of this bizarre phenomenon?