Sigma does not recommend TC use with this zoom. I've tried a decent Vivitar 2X Macro TC behind it near 300mm. Very soft.
-Lon
[EMAIL PROTECTED] wrote:
I have the Sigma 70-300mm APO Zoom. I would like to put lens converter behind it, probably a 1.4 or 1.7 so I can try to preserve AF. My question is whose do I use? Sigma to match optics(?) or the Pentax or is there another I should consider.
John Graves
