Originally posted by m8o So has any reader of this thread who also owns the 2nd (or is it 3rd) gen of this Sigma lens, specifically with the HSM, used it with the Tamron Pz-AF 1.4x MC4 TC or any other TC with the Pz connection? I seem to remember reading posts that it acutally 'slows down' HSM focusing speed?
Yes, I've tried it with the Tamron TC: it works but really not all that well in terms of AF speed and "lock on".
Also, I suspect (on a purely "after the fact, therefore due to the fact" basis) that using it with that TC
may have had something to do with the HSM issues that developed with that lens his year (fixed by Sigma under warranty) so I've decided not to try that combination again. It's no really loss as far as I'm concerned--I'm really after the native zoom range and it performs beautifully there.
Interestingly, the lens seems to be sharper wide open since I got it back from repair--here's a 100% crop: