Yashica Dental-Eye, great collectors item.
 
The Dental Eye cameras were a series of specialized SLRs for 35mm film from Yashica, later Kyocera. These designs replaced the Oral-Eye series of cameras that was adapted from the Electro 35 and distributed by dental equipment company Tokyo Shizaisha.
The design was optimized for medical and scientific applications, adapting a Yashica SLR body but with a fixed macro lens. The lens barrel included a ring-light flash, around the lens' front element.
None of the Dental Eye models can be focused to infinity. They operate only in the close-focus range, down to 1:1 magnification.
Yashica Dental Eye (original), 55mm f/4.0 lens. Based on the Yashica FX-3, Lever film advance. Farthest focus is 1:10 magnification. Aperture is mechanically linked to focus distance.