Originally posted by Marc Sabatella it's notoriously difficult to get exact focus with a mirror lens.
Which is why I put metal tape on my Sakar 500/8's T2-PK base and always use CIF with it. And use it in bright light. I just did some shooting in a downtown and got some very nice results with brightly-lit targets.
Originally posted by yusuf Actually it's an interesting thought. Although a focal length is a focal length, wouldn't the shake observed by the sensor will be more in the center part compared to a full frame.
The SR system in my K20D doesn't care what camera format a lens was designed for, nor how it is built, nor how it is being used. If I build a 35/0.9 lens by stacking +30 dioptre closeup lenses on a focusing helicoid and enter 35mm, it's stabilized (but soft). If I put 60-75-90-105-127-140-162mm enlarger|projector lenses on bellows and enter the closest FL, they're stabilized. If I put MF lenses on adapters and enter the FL, they're stabilized. If I put a 12-inch LF lens on extension and enter 300mm, it's stabilized (but heavy). If I reverse an A35-80 zoom, set to 75mm and I enter 75mm, it's stabilized.
ONLY THE FOCAL LENGTH MATTERS!