I use the Sigma 1.4X APO and 2X APO converters with my Sigma APO 300/4. I am very happy with the results and would suggest matching the TC to the lens. Sigma's docs suggest that AF is preserved with the 1.4X on Pentax with the 300mm but not with the 2X. In my experience with the *ist D AF works with this lens and either TC (I don't use AF with the lens, I was just playing around one day).
Christian ----- Original Message ----- From: <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Thursday, March 04, 2004 2:00 PM Subject: Lens Converter > 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 >
