I have another optical project ongoing, too, a relay-lens system for a "periscope lens" using a 1.7 mm fisheye lens for GoPro-type cameras. Here, too, ML's 3x function enables full-frame video from that tiny lens.
However, it necessitates quite an optical construction, here assembled on a piece of angle iron, working as an "optical bench":
Explanation: Furthest from the camera, at left, is the 1.7 mm fisheye lens, diameter only 22 mm (7/8"), then a 20 mm Bolex 8mm projector lens that focuses the image from the fisheye toward the relay lens, which is from a laser copier. Then follows an objective lens from a small binocular, which collimates the light toward the actual camera lens, which is the rear part of a C-mount video "pinhole" lens. The pink rings are just holders for the components, all turned to 22 mm diameter. The angle iron is attached to the camera lens with masking tape - simple, but workable for this test!
Since all the optical components are achromats, the chromatic aberrations should be minimal. There is quite a bit of spherical aberration, though. I already know that the edge sharpness won't be perfect, but the intended use is for closeups of flowers and insects, still showing a relatively in-focus background. A 1.7 mm lens has an incredible depth-of-field (2" to infinity) even fully open - which in this case is around 5.6 to 8 due to all the optical components.
I'll post a video when I get the project finished - I will yet have to make a system of threaded tubes (total length about 250 mm, 10") in order to do a final assembly - thanks to my hobby lathe, that should not be too difficult a project...
Demo video here:
https://www.magiclantern.fm/forum/index.php?topic=26804.msg242418#msg242418
