Lorin, The screw mount for Spotmatic cameras is commonly known as "M42", "Pentax screw" and "universal screw". M42 refers to its diameter, 42mm. There are many excellent lenses with dedicated M42 mounts, and you can also get M42 adapters for other lens mounts; such as YS and T variants, and even some medium format lenses (e.g. Pentacon 6). I'm pretty sure you can also get an M42 adapter for Tamron's Adaptall mount, but possibly not for Adaptall II.
here are some good sites to visit for more info: http://medfmt.8k.com/third/mounts.html http://medfmt.8k.com/bronmounts.html http://www.aohc.it/tak00e.htm http://www.gate.net/%7Ehifisapi/lens1.htm I'm not sure what you mean by "long focus". I have personal experience with the following 200 & 300 mm lenses: 200/3 Vivitar Series 1 VMC [Komine] M42 200/4 Meyer Orestegor M42 300/4 Spiratone YS 300/5.6 Tamron SP Tele Macro (mod. 54B) Adaptall II The 200/3 Vivitar Series 1 and 300/5.6 Tamron SP are absolutely excellent. I like the 200/4 Meyer, but still haven't made up my mind about it. The 300/4 is fast, but not nearly as good as the SP. Jim www.jcolwell.ca
