04-04-2014, 11:27 AM
It appears the rubber collar of the TC's outermost lens impinges on the collar behind the Sigma’s rear lens. Do the Sigma’s rear elements move? I am uncertain and that is why I didn’t use the combination. My goal is to have a tele/macro in one package for backpacking. I want to do macro and immediately change to tele if interesting wildlife happens by. I have AF with my Canon 70-200 + 2X TC; why would I not have AF with the Sigma? Thanks for the comments!