Sigma TC-2001 2x Teleconverter

Autofocus still works reliably even when paired with a slower f/5.6 lens, which was my main worry. The two special low dispersion elements keep the image surprisingly sharp for a 2x teleconverter. Dust and splashproofing gives me peace of mind shooting outdoors.

I’ve been using this teleconverter with my 70-200mm and the autofocus still works reliably up to f/8, which surprised me. The build feels solid and the dust and splashproof rating gives me confidence on rainy shoots.

Sharp as a tack at 2x with my 70-200mm, and the autofocus still locks on at f/8 without hunting. The two low dispersion elements really keep the color fringing to almost nothing, even on harsh backlit shots.