Ian, if your taking lens accepts 52mm filters would the Aivascope just screw right in, no need for step up rings? Also, since you focus via the taking lens shouldn't autofocus work? I know you probably don't use autofocus, but the reason I ask is I'd be interested in using it for photography, not filmmaking. One final question. I know they recommend it for use with sensors no bigger than m43. Any idea how fast of an aperture you can use with m43 before the image is unusable? Wondering if f1.4 or f1.7 would be okay. No problem if you can't answer these questions, still appreciate you starting this thread.