The problem: The tele-converter works fine with the Sigma Tele but will not work with the 18-70DX (continually hunts for focus)! The question now is that I wish to get into a 28-300 macro tele! Both Sigma & Tamron have now both gone to Digital signing! Will these new lenses still work with my tele-converter, or should I look for one of the earlier D type macros(aprox 12 months old)???
Any suggestions on which brand is best between the two?
Cam.
