Fred <[EMAIL PROTECTED]> wrote: >> I have the Pentax 1.7x AF converter and the two Sigma >> teleconverters (1.4x and 2x) that they make for their "big glass" >> (300/2.8, 500/4.5 and 800/5.6). > >Mark, are these Sigma TC's autofocus TC's, or manual focus (only) >TC's. And, do the Sigma TC's have the protuberances like the big >Pentax 'L' TC's do?
They're both AF. Neither one protrudes like the Pentax "L" converters do, but the glass in the 2x comes right up to the flange, so it doesn't fit on some lenses. It'll barely go on the FA*80-200/2.8, but the lens can't achieve infinity focus with this TC attached (I have no idea why). I now use this TC only with the Sigma 300/2.8 (which is what it's designed for). I've never tried the 1.4x on anything other than the Sigma 300. -- Mark Roberts Photography and writing www.robertstech.com
