Mounting Enlarging Lenses on EOS Cameras -- Quick Update

Airmail package from Hong Kong came today. It contained an adapter that allows me to convert an M39-type lens (like those typically found on enlargers) to an EOS camera mount. Got mine off of eBay for $10 including shipping. It's a relatively thin brass ring -- does exactly what it the ad said. However, this particular one I bought is thin and a bit tough to get off the camera, not much to grasp on to when I try to twist it to remove -- other than that 'tis straightforward to use.

Here's a word of warning (learned from observation, not by making this mistake): Many of the enlarging lenses that I own have a bit of metal / element that protrudes back behind the screw mount. If placed on the adapter and mounted directly on the camera, this element would protrude back into the body of your camera -- something that typical lenses don't do. The quite real danger here is that the lens could actually protrude back far enough to get in the way of the mirror as it flips up -- the lens would probably be ok, but the mirror and camera would really suffer after the mirror slams against the lens. This is the same warning that Canon gives folks with their EF-S mounts -- there can be mirror collision if one of these EF-S lenses is mounted on full frame EOS cameras. Some of the enlarging lenses I have sit really far back, probably enough to damage all types of cameras, not just full frame ones.

The only solution I readily see is to use these protruding lenses on some sort of extension tube or bellows to get them off the body of the camera and away from the mirror. Didn't check out all my lenses, but I did find one lens (the Taylor Tayon 75mm) that didn't protrude.

I started playing with various combos of lenses and extension tubes, but it's a bit late and dark and I'm not up for doing a whole lot of testing tonight. In general, this line looks promising, and I'm getting good macro effect. The tubes are pretty static for focusing, so I still think some bellows will help fine tune focus.

Will report back with some photos later this week.