This is an untested (I will test soon) adapter to allow attaching the Canon macrolite to the outer barrel of the EF 50mm f/1.4 lens. This lens is unable to support the macrolite at the filter threads, so this adapter supports the lens at the hood bayonet.
Well, I tested the first version. We are almost there. The fit was too tight to the lens (I almost didn't get it off) and the macrolite would not fit on the end. I've fixed those things, I think. I checked for vignetting. Didn't happen as far as I could tell. So that's a good thing.
Now, the second version is getting printed and tested. the second version is 1mm longer, so it might start vignetting, but I doubt it.