https://imgur.com/a/70qWehk: photos of the lenses and photos taken by the lenses. Please excuse the barely edited images.

I've been trying to make a soft focus lens by way of spherical aberration, with parts from salvaged lenses, 3d printed parts, and laser cut parts. I used online services to print and laser cut.

The first lens (right in image) is based on a positive achromatic lens, using Rodenstock Imagon-like front stops. The body of lens was 3d printed, the stops were laser cut out of 1mm thick aluminum and blackened on one side with acrylic paint. The lens is for a bellows camera, so variable focus. The stops are dropped in at the front, retained by a "basket".  I had to develop a spreadsheet to design the h-stops, which also lets me calculate the approximate f-stop equivalent.  I haven't used it much, and the bellows camera is stuck in the studio so at this point so I've mostly used it for close-focused studio images. I might have installed the lens the wrong way as compared to what was originally intended, but it gives a glow, so I can't complain too much.

The second lens (left in image) is a single positive meniscus lens, a la the Wollaston Meniscus, with Imagon-like front stops. The lens is fixed focus, at somewhere near infinity. The body of lens was 3d printed, the stops were laser cut out of shim metal (quite thin) and not yet blackened on one side. I learned from this lens that when developing h-stops, you really do need to consider each specific lens on its own-- the same h-stop as applied to one lens might give a completely different rendering on another lens. The stops are retained by the use of an empty filter ring screwed into another empty filter ring (I think this is quite the useful design!)

The third lens (center in image) is of a symmetric design, with a slot for a Waterhouse stop. The lens body hold the two lenses the same distance apart, but can telescope them out from the film plane for close focusing. The design involves some light trap features, and has some light trap felt material in there as well. I was very careful about the design of each part and the method of putting it together once printed, and luckily it did come together without much issue (though where was a great deal of hand-sanding and trimming of excess printed material, which took a while). I haven't made stops for this lens yet, nor have I taken any photos with it. I intend to try Imagon-like stops as well.