I have a Tamron 1.4 extender. I almost never use it unless I'm going to have a fixed focus. There are a couple of things at issue: first, it won't work with EF-S only lenses like my 18-200. You can't even connect them. Second, in order to make autofocus work, you have to tape off 4 pins inside the extender. That's not real bad, but the autofocus becomes so slow that it's next to unusable with any kind of action shots and frustrating for general purpose photography. Maybe you're more patient than I am. Third, this isn't just a factor with the Tamron extender. Same holds true for the Canon version. Finally, the 2.0 extender has had some negative reports of chromatic fringe aberration. I've seen that happen in other extenders I've used with different cameras.
My advice? Bite the bullet and buy the good glass. As a friend sez, "buy the best and only cry once." Doesn't mean that ya have to go buy a 600mm f2.8 (but if ya do, I wanna borrow it <G>) but the 100-400 will provide infinitely better shots than a 2x extender on the 70-200.
Just my opinion, your mileage may vary. RtR(who can almost see out of 1.25 eyes now...use your imagination to set the ratio)
At 11:46 AM 11/18/2009, you wrote:
I'm considering a tele extender for my 70-200mm Canon lens. Has anybody had any experience? Canon makes their own but Sigma also makes one and it's about $100 less than the Canon. Any experience?Michael -- Michael Wells MCWells Photography <mailto:mcwellsphoto@xxxxxxxxx>mcwellsphoto@xxxxxxxxx 801-850-7279
