1. Albinar 28mm @ 1:2.8
2. I tried several iris settings, i usually got less worse results on open iris or 1.4...2.8
3. I don't use any shutter.
4. Unfortunately I don't know much about the brevis itself. It seems to be an old version like rev.1 or rev.2, i'll post some pictures or a video to show the problem.
When I follow the instructions for grain reduction, I try to speed up oscillation (inside of the brevis), but then it suddenly changes to a high buzzin but almost no vibration. When I reduce speed till minimum it (sometimes) vibrates properly again but with heavy grain. Can it be a defect of the motor?
I'll post some footage, maybe this'll show...
Thanks for your help!