just got a tamron 1.4 teleconverter and it will AF on my tamron 200-500 so hopefully tomorrow it won't rain and I can see how it does at forsythe now with an effective reach of 1050mm. it is now minimum fstop of f9 instead of 6.3 it will also af on my tamron 70-300 f4 to f 5.6
did a quick test of it on the back nest using the tamron 200-500 and the 1.4 no cropping done. I can see I am going to like this as it gets me really close taken at 1/1000th at f10 ISO 2000
yes. it is ok for birds sitting still but trying to get a focus lock on them in flight is almost impossible