Posted by Justin Miller on January 01, 1970 at 00:00:00
It should work, though I don't have experience with that exact camera and lens - generally, all DSLRs I know of will autofocus properly at anything less than F8, and the 1.4x TC with that lens would stay below that threshhold. I don't think any longer TC would work reliably - a 1.7x would probably only work sporadically and unreliably, and a 2x TC probably not at all. I've shot with a 70-400mm F4-5.6 and a 1.4x TC on another DSLR body, and it was able to AF, though mostly in good light - in testing in some lower light conditions, it became more unreliable. You may encounter the same with that combo - in less than good light, it may struggle a bit more, but in good, bright Florida sun, it should work OK.