i have all three of these. the 80-320 is a lot lighter, but shows more edge light falloff until stopped down 2 stops. my 80-200 has falloff one after 1 stop. the 80-320 also stays soft in the corners, especially at the long end, until stopped down 3 stops. it's noticeably less sharp across the entire focal length range even on the *istD. however, it is 1/3 the weight. i find the Sigma TC to produce very distracting bokeh on my 80-200. i'm starting to switch to Pentax TCs even though i lose AF ability.
Herb... ----- Original Message ----- From: "John Francis" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Tuesday, March 23, 2004 11:40 PM Subject: Re: USA shopping list... > Despite all that, though, it's the lens I use most. It even performs > tolerably well with the Sigma 1.4x AF TC (although I suspect that the > 80-320 I accquired recently will probably do nearly as well, and be a > great deal easier to carry).
