CI Photocommunity

Register a free account now!

If you are registered, you get access to the members only section, can participate in the buy & sell second hand forum and last but not least you can reserve your preferred username before someone else takes it.




Hi. I am looking at using an RTSII (with fully mechanical B and mirror lock-up) to do both prime focus photography with a telescope and with Zeiss lenses. I have some questions that I would like to ask other Contax/Zeiss users:

1. What experiences have you had in the past with astrophotography with Zeiss?
2. Which of the moderate telephotos: 85, 100 and 135, has good performance. I guess it is measured by objects at infinity, with very little coma, chromatic abberation, astigmatism and spherical abberations (The Siedel Ones).
3. Which f-stops have you found with the various lenses that gives optimal perfomance, under the above criteria. Given that a faster f-stop is better for exposure times.
4. Which other lenses and f-stop combinations would you recommend.
5. OT: Which slide film gives good performance for you?

Thanks so much for sharing your experiences and thoughts.