Last month I bought a tele lens 6,3/400mm from the '60s-'70s made in Japan, its commercial brand is according the importer: Hanimex, Soligor, Vivitar and others; mine is "Hanimex", an importer from Australia; it has M42 mount and then my topic about the Rollei M42- QBM adapter. This tele lens is long like a canyon and heavy. It has a ring with a tripod socket but I used it camera hand-held (not recommended, it requires a tripod). I was only checking it for the first time, I had a Kodak Pro-image ISO 100 loaded in the Rolleiflex SL 35 E (the tele lens requires an ISO 400 film at least). You need 1/500 or faster shutter speed to eliminate camera movement in the image; if you are using an ISO 100 film, you are limited to the lens f stop full aperture, f 6,3, for subjects in shadow. I took these two photographs about birds in the wild last week- end in the farm; they were taken with the Hanimex 6,3/400mm, camera hand-held, lens wide open f6,3, 1/500 shutter speed, Kodak Pro-Image ISO 100 color negative film, and the Rolleiflex SL 35 E with the Rollei M42 adapter, It's not easy to take photographs about birds in the wild, I'm starting to learn: https://www.flickr.com/photos/itarfoto/16386867475/ https://www.flickr.com/photos/itarfoto/16199455170/ Carlos