Browsing on the Surplus Shed website I stumbled on this lens. Its not very impressive looking but the seller said it was made by Tomioka, a Japanese manufacturer that makes some seriously good lenses. The lens was only $6, I decided to try a couple of them.
This lens was made for a US optics company in the Tomioka factory in Japan, and the surplus stock was eventually found its way to Surplus Shed. The lens called the 32 MM FOCAL LENGTH LENS ASSEMBLY on the Surplus Shed site, and is covertly labeled Yashinon. Thats a good thing since the Tomioka factory was bought out by Yashica, and later Zeiss took over control of the same factory to produce the Contax lenses in Japan, which were Zeiss’s flagship 35mm format lenses.,
There is no name engraved on the lens barrel, but if you closely you can part of the lettering on the front inner trim ring that reads; Yashinon 1:1.7 f=3.5cm Japan, but the lettering has been painted over, you can still see the lettering.
This lens is sharp, the sweet spot seems to be about 3X, reverse mounted. The image circle covers the APS-C format, no problem. The field is very flat. The corners are pretty good and CAs are pretty well controlled. At 3X, this lens beats most 6 element enlarging lenses I have used.
Next week I will be posting a comparison of this lens against 6 others at 4X.
The lens is in stock at the Surplus Shed website: https://www.surplusshed.com/pages/item/L13698.html
You might want to order one or two while they are still available!
Surplus Shed Yashinon Tomioka 32mm f/3.5 Lens
Surplus Shed Product Code: L13698
Filter threads: none
Retail price: $6. Plus shipping.
Yashinon next to an typical enlarging lens for scale.
The lens is in a straight barrel mount and has no threads, but luckily, I happened to have a plastic Raynox 37mm to 34mm step down ring that slips tightly over the barrel. The adapter is thick enough that it will keep the lens straight, as I was able to make images that are sharp corner to corner, but I would recommend being careful not to bump the lens while you are shooting, just in case.
This exact Raynox is the RA3734, 37mm to 34mm Step-down Adapter Ring, part number: RA3734
But this adapter I own has been discontinued, but Raynox has a replacement, the RA3734P5, that should fit the lens okay but I have not used the replacement.
Mounting is easy with a few cheap adapters, here on a Sony A6300, left to right, E-mount to M39 adapter, Canon M39 extension tube, 39mm to 42mm step-up, 42mm to 37m step down, and the 37mm to 34mm Raynox step-down adapter.
This Yashinon 32mm has a fixed aperture of f/3.5. It looks like this lens is really a f/1.7 lens but has an f/3.5 or smaller waterhouse stop (aperture disk). The rear lens group is pretty easy to remove with a spanner wrench, giving you access to the aperture disk. The disk is not removable, the only way to enlarge the aperture would be to drill out the disk.
To order this lens of for more information, follow this link to the Surplus Shed's site: https://www.surplusshed.com/pages/item/L13698.html