I recently read reviews on Canon EF12 II and EF25 II extenders, and there seemed to be an issue with their fit on L glass lens. Some reviewers reported difficulty in mounting them to L glass lens because of very tight fit. Supposedly there was no such issue with the older non type "II" extenders.
One reviewer stated he talked to Canon and learned the type "II" extender mounts had been altered slightly to better fit EF-S lens, resulting in the L glass fit issue.
Can someone using extenders (old or new versions) comment on the validity of this issue. I wanted to get a set for use on a 500 F4.
Comments greatly appreciated - Have a blessed day - dave b.
I've used both EF 12 II and EF 25 II on my 500 f4, 100-400 IS and 100 2.8 macro, and I'd say these are just a bit tight fitting. The fit is somewhat tighter than any of my Canon II, Sigma and Tamron 2x/1.4x TC sets, but not so tight that I'd be alarmed.