Thanks for the advice. I'm just looking for a 35mm body to use with my recently-acquired Mamiya 50mm macro lens ($20 in an antique shop, including matching extension tube). Maybe I'll build a "Mamiya Z-to-Nikon F" adapter out of some Nikon extension tubes so I can use this on my Nikon with aperture control. The aperture ring doesn't adjust the aperture when the lens is not mounted to a camera, but I've got a way to manually set the aperture with a bent paperclip.