Has anyone on the list had experience using a TC-14a or TC-16a with the AF 180 ED 2.8 (non-D if it matters)? I have tried a few shots w/ the TC-16a and some show vignetting, some don't - I suspect it has to do with shutter speed, though I can't see how. Does the TC-14a exhibit similar behavior? Is either more usable than the other? (I'm trying to avoid carrying my 80-200/2.8 to Uganda in a few weeks - I will probably carry my 70-300/4-5.56, but would rather carry some faster glass as well - either the 180 or the 80-200, along with a TC.) Thanks, Bill Boyle
