Jeff wrote: I wonder which one [(49 or 55mm thread)] is older. I have the 90/2.5 with the 49mm thread, model 52B.
Jeff, I've identified four Tamron 90mm macros. It's not clear All appear to have used an optical formula of 10 elements in 9 groups, treated with BBAR (Brad Band Anti Reflection) coating: Manual focus models: 1978 (only): Tamron Tele-Macro, 49mm filter and 1:1 2X multiplier (Adaptall?) 1978-1996: Tamron SP Macro, 55mm filter and 1:1 tube (Adaptall) Autofocus models: 1996 (only): SP-90 AF Macro, fixed PKA Pentax mount (rare), 52mm filter, 9-blade aperture. The sharpest Tamron macro, rating 5 out of 5 in an online test vs. 4.5 for the manual-focus model that used a 55mm filter. Fall 1996 to present: SP-90 model 72-E, autofocus, Adaptall mount, 9-blade aperture, 55 mm filter. [EMAIL PROTECTED] -------------------------------------------------------------------- mail2web - Check your email from the web at http://mail2web.com/ . - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
