Hi all, disagree I think. From Canon UK website it states
“If you see a red circle on the lens mount your camera will accept EF lenses.
If you see a red circle and a white square it will accept EF-S lenses as well.”
I have mounted the lens, it fits and fires, but just read on line that some cameras and lenses, the lenses can damage the mirror.
Its a canon 6dmk2 and a tokina EFS lens.
The guy I got it from stated he used it successfully on a canon 5d (not sure of the mark), but these are all full frame.
I do accept that at very wide settings it had vignetting.