Tomioka Tominon 17mm F4 (17tt)

I just pulled out a Tominon 17mm f4 lens I bought as part of a full set that was used with the Polaroid MP4 system. The lenses are generally very good, though the 135 and 105 are middle of the road in quality. The 75 is very good, a bit better than a 75ELN, while the 35 is even better and covers up to 5x well. I generally don't go beyond 4-5x, as that covers the "money shot" for Lincoln RPMs where the entire date and MM can be captured in a single frame. But since the Tominons seem to keep getting better as focal length shortens, I thought I'd try the 17 at minimum magnification to compare. As it turns out, the 35 is good wide open, and the 17 follows the same trend. At f4 it looks excellent, and is sharp enough to require a 6-image stack. Here is an example image using the 17TT at the lowest magnification I can achieve on the bellows:



The 17TT has three problems:
1) It has a built-in extension that I suppose is designed for parfocality with the 35TT, but limits the minimum magnification to around 6x
2) It uses the Copal-1 shutter thread (M40x0.75) so requires an adapter
3) Working distance is pretty small since the focal length is so short