Triggered by a question in the Forum , and a post on The Digital Story discussing that the bajonet mount lenses of analog Pentaxes fit the Pentax K100D Digital SLR, I had a look on eBay. If you search for “adaper EOS”or “adapter Nikon”, all kinds of adapters turn up for using old lenses on digital cameras. For example on the digital Canon EOS models,  or for fitting a Hasselblad lens to a Nikon D50.  Wouldn’t it be fun to experiment with those old M42-mount lenses from Carl Zeiss Jena and many others?

PS. A cross-reference of mounts and lenses is in Steimer’s Fotoliste discussed here.  Other websites covering lens mounts are in the Vintage Camera Online links section