A rare (and unusual) industrial lens is the Repro-Nikkor 85mm f/1.0, which is somewhat of a one trick pony. It weighs a whopping 640 grams (1.41 lbs.) and is faster than probably any lens you own. It is amazingly sharp, but designed for only a single reproduction ratio, that of 1:1. It is entirely reversible; you can mount it front or back and it can serve as a relay lens.
The Repro-Nikkor has an unmarked aperture ring that goes from f/1.0 to f/8, and the lens itself consists of 12 elements in 8 groups. The lens has 53mm external threads, with 48mm internal threads. The lens is five inches long, with a diameter of 2.5 inches, and is built like a tank, an elegant one at that. To hold one in your hand is an experience. It is so heavy.
As a reproduction lens, it was designed to function from 0.9x – 1.1x at a standard wavelength of 400 – 650 milli-microns. The lens is highly corrected, because it is a super copy-lens, with o% distortion and 0% vignetting. It resolves at an incredible 200 lines/mm and has an image area of 24mmx36mm (42.2 mm circle). The lens has an overall working distance of 8.82 inches and no way of focusing it.
In other words, it has no helicoid, but it can be mounted directly on the camera-and-a-focusing rail or on a bellows system. You won’t find a clearer lens with more light in your viewfinder, anywhere. And now for that one-trick.
Since it is designed only to be used at a 1:1 reproduction ratio, you don’t need to own it unless you want to work in a true macro range at exactly 1:1, in which case it is sharper than sharp, with a strange ethereal quality when used wide open. It has very limited range of use. The Repro-Nikkor is a very specialized lens. It does one thing very well, but that’s about it. I happen to like that one thing… a lot. It turns up on Ebay once in a while.
Here is a couple of images with this lens, a photo of it, and a quick shot of it mounted on Novoflex Castel focusing rail with the Nikon D810. The camera sits on the Swiss-Arca Cube C1 geared-head, on a RRS tripod. There is an old Zacuto Z-Finder on the back, to help magnify the LiveView screen.