View Full Version : Is there a difference between the ground glass spinning or vibrating?
2007 December 16th, 15:38
I am looking into the 35mm adapters and I was wondering if there is any true difference or advantage of either a spinning or vibrating glass. Or is the same function/outcome?
2007 December 16th, 16:11
Use the search and read the threads.
All the information is here just waiting for you! :hv20-smilie77:
2007 December 17th, 02:27
Spinning is probably better as disguising imperfections on the focusing screen, but the balance must be absolutely spot on otherwise the focus will "pump".
Vibrating is easier to align, and the focus won't pump, but imperfections may still be visible.
2007 December 17th, 05:07
wow thanks, very much appreciated for your insight. couldn't find much so far. been searching, but not even 1/10 through the threads. thanks!
2007 December 17th, 06:27
Most of here are using simple vibrating or static designs based on the great work of Daniel at www.jetsetmodels.info.
2007 December 17th, 12:12
I would say, from experience, if you can seal the chamber then use the vibrating instead of rotating. I think it's all a matter of material. I own the Redrock M2 as well as make my own static adapters. The material that the spinning disc on the Redrock is made of, is just not as clear as actual focusing screens like the ee-a or ee-s. It also creates circular patterns in some backgrounds (I have no idea what this is due to but I speculate it is in the material used). A focusing screen produces a much better image, it's brighter, and there will be almost no vignetting if you use a good achromat.
2007 December 17th, 12:37
What tkmslee said,
I've been playing with a friend's HV20/Brevis combo for a couple days now, it's quite bright and, once we fine-tuned the back focus, acceptably sharp with none of the brightness/focus "pumping" I've seen from spinning adapters like the M2. We haven't really 'shot in anger' with it yet, but I'm kind of enjoying shooting prime lenses instead of the zooms I'm used to.
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