I really like these 35mm F3.5 enlarger lens. They are compact, fairly sharp wide open and it is a fairly well corrected design with no colour fringing in the out of focus areas and also minimal focus shift from UV to visible light. Hence ideal for adapting for imaging.
These enlarger lenses come in 2 designs (older and newer body), but both have the same optical formula (triplet) and lens coatings. It can be found under many different brands. The ones I have are: Aico, Beslar, Soligor, Phago, Vivitar, E-Ikor and Spiratone.
Most of these have M39 male thread mounts, except for the Spiratone which has T2-mount (42mm).
Below are images of the lenses mounted on the Sony A6000 and Olympus E-PL5 to show how big (or rather how small) they are when mounted with a focusing helicoid. With the helicoids on the Sony and Olympus systems, I am able to infinity focus and close focus down to between 15.5cm for Olympus E-PL5 and 13.5cm for the Sony A6000 (measured from the camera mount to subject).
There are quite a few ways to mount filters to these lenses e.g. for UV-imaging. All are methods I have used.
1) Epoxying a 25.5mm frame to the older version lens. Then you can either use 25.5mm filters (which are cheaper) or use a step-up ring to adapt to larger size filters.
2) Using the M42/C-mount to Micro 4/3rds adapter, by mounting a 25.5mm filter into the C-mount female threads of this adapter.
The benefit of this method of mounting filters is that it is protected and does not add to the bulk of the lens. But it also makes changing filters less convenient. This method of mounting is hence ideal for a one-filter system, perhaps solely for UV-imaging.
For M42/C-mount to Micro 4/3rds adapter click link here: M42/C-mount to Micro 4/3rds adapter
Click links below for suitable 25.5mm filters (you can combine the S8612 and either the U340, U360 or UG11 for a good UV-pass filter with enough IR-suppression – much cheaper than Baader U filter). For reference, I use 1mm U340 + 1.5mm S8612, which already gives enough IR-suppression:
3) Using MagFilter adapter to mount a filter to this lens. The filter system can be stored separately so it does not add bulk to the system, and buying a few of these will allow for different filters to be used.
MagFilter 52mm filter adapter link UK here: MagFilter 52mm (UK)
MagFilter 52mm filter adapter link (rest of the world) here: MagFilter 52mm
4) Using adapter rings to form a filter mount.
Link to Xume 49mm starter kit: Xume 49mm starter kit
For further information, please read this post: Stepping rings and its uses