I had a canon rep say a few things about off brand lenses.
1. "you use a flash with that Tamron?" "How's it metering?"
And went on to say it'll be off.
I've heard of Canon brand Flashes doing better metering, but not lenses. Isn't AF and metering almost entirely the camera body's job? I realize there can be issues like "front focusing" that are the lenses fault, but not sure where the line is drawn. Logic would suggest that the flash metering wouldn't care what lense was used as long as it knows the focal length, f-stop, and shutter speeds. The light meter is in the camera, not the lense.
2. She also mentioned that "Tamron only uses the center AF". It can be rechipped to work OK but ... "It'll look like its using the others but it doesn't really".
I use my Tamron 28-75 f2.8 about 90% of the time. I use center AF more than not but hadn't recalled a problem.
Upon trying it; all of my 9 AF points work as I would expect. If I select the far right one, focus on a series of objects at varying distances, it focuses immediately on the one at the right dot.
3. She said that Tamron has the same owner as Nikon and they share specs to make the Tamron work well on Nikon (Mitsubishi). The suggestion was that only Canon lenses would be 100%, and that Canon doesn't share its specs so they would have to reverse-engineer the lenses to work (sounds fishy - wouldn't Canon want their bodies to be the best and not be blamed for lense problems?).
Was this just sales talk or is there really something to it? My BS meter was waving its hand, but these things usually have some element of truth too.


