|Posted: Mon Jun 20, 2022 9:13 pm Post subject: Mystery Lens - Optical design
I've been playing around with a small lens of unknown origins I found in my boxes of bits, it's in the form of a pair of optical blocks and looks to have come from some sort of machine. It was filthy so I gave it a good clean and in doing so, had to take it apart, so I sketched the optical layout, just out of curiosity.
The lens throws an image circle of around 25mm diameter and changing the spacing of the two blocks changes the focal length. With the two blocks placed together touching, the focal length appears to be around 20mm, moving them about5mm apart appears to change the focal length to about 25mm.
Anyways, the layout is unusual to my eyes, or at least, the back half is, the front is similar to a typical modern wide angle. In total, it has 8 elements in 8 groups.
Just wondered if anyone had seen anything similar before or had any useful comments.
I don't care who designed it, who made it or what country it comes from - I just enjoy using it!