I posted the following at Flickr, then thought I'd have better luck here... I recently purchased a Mitakon/Zhongyi Lens Turbo II 1508 focal reducer to adapt Minolta SR mount lenses to a Sony E-mount camera (NEX-6). I was immediately surprised to learn that there is mechanical interference between the glass element of the Turbo II and some of my favorite Minolta lenses. This seems to occur on any lens that protrudes the slightest distance behind the bayonet when focused to infinity. This is the case on Rokkor 28mm f/2.8 and 50mm f/1.4 and f/1.7 lenses. I don't think it occurs on telephoto lenses. It's also not a problem on a Rokkor 45mm f/2.0. I'll need to check a few more lenses, and I guess I'll need to put stickers on the lenses that turn out to be compatible. Otherwise I may grab one that isn't compatible when I'm in a hurry and cause damage to the lens and/or focal reducer. I don't think there is a solution to this other than avoiding those lenses. Unfortunately, it was those wide and normal lenses that I most hoped to use with the focal reducer. On a few lenses, the depth of field preview lever contacts the metal lens surround of the Turbo II, causing the aperture to jam open. I had heard reports of that before, and observed it on at least one lens. I'll need to shorten those levers with a file (taking care to avoid leaving filings in the lens!). I'd like to hear from anyone else with similar issues or links to discussions. It anyone aware of a list of compatible and incompatible lenses?