Here (unedited) are some Adaptall mount comments I saved between 1996 and 1999:
Richard Ross: �The stopdown mechanism on the KA Tamron mount is cantilevered in such a way that it is possible to close down the aperture on a lens and not have it fully open when the lever is released. I experienced this with my MX and the new Tamron 90/2.8 lens. The spring-loaded aperture in the lens itself is quite delicate, and the cantilever in the KA mount was sufficiently stiff (or perhaps not smooth enough) to prevent full release. I examined three samples of the KA mount and they all displayed this behavior. The whole thing worked perfectly on my Program Plus.� David: �I have experienced the same thing as Richard has described with KA mounts. It happens on most of them, some of the time. By the way, I transferred the aperture scale of a Tamron K mount to a KA mount. It works just fine and is useful for those with Super Programs as well as MX/LX cameras. I often wondered why Tamron doesn�t have a combination mount.� Roger Stockton: �There is a bit of play between the K adapter (Adaptall 2) and the lens, which can feel annoying when focusing, as the lens can turn ever so slightly before the focus ring turns.� Tamron mounts are available used from B&H for $22.50. Lenses made for Adaptall-1 will take Adaptall-2 adapters, but it will not meter on some cameras. Doug Hohenstein: �There is a problem [with my Tamron SP-17]. When set to AE on the lens, with a P-KA adaptall mount, the coupling slips out. Also, the camera does not detect the auto-aperture mode as identified by the inability to put the camera into a shutter-priority mode.� John Papandreou replies: �I have a number of Tamron lenses and they are all very nice. The problem I would say is with the mount. My PKA mount had dirty contacts when I got it at a bargain price for that reason. If cleaning doesn�t work, buy a new mount.� Tamron Adaptall 2 mounts for Pentax KA have been known to cause exposure problems if the smallest aperture is smaller than f/22; f/32 is interpreted as f/22. Try to buy it new. The KA mount cannot support apertures smaller than f/22 because the 32 setting doubles as the A (auto-aperture) setting. The PK mount has a much smoother aperture stopdown mechanism. It also has a second aperture scale right on the mount base so you can view the aperture in KX, LX, and MX viewfinders. Steve: �Beware of weak springs in old mounts. The iris in the lens defaults to open and the pin needs pushing to stop the lens down. With the PK adapter this solely relies on the spring in the mount. I think the PKA adapter performs better in this respect. The mounts can be a bit of a fiddle but are straightforward to change. I think it comes down to ones own patience if this is a problem or not. I know someone who is quite happy to have one mount for his several lenses. That's not for me.� �Tamron PKA adaptall mounts don't have the A setting per se. The minimum aperture defaults as the A setting, and is usually (always?) a different colour from the other aperture numbers.� --William Robb [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 .
