Monocle for SLR / DSLR cameras, made of the body of old soviet lens Helios-44-2. Set on a mirrorless camera via an adapter.
This monocle has the unofficial name "classic" thanks to replaceable diaphragms. It is also called "Kolosov's monocle". By the name of George Kolosov - a living classic of pictorial photography. The master who first made a monocle for small-format cameras.
The monocle can be used as a portrait. It has high levels of contour sharpness and spherical aberrations.

Replaceable diaphragms on this monocle are wound in front, as well as light filters. The set contains two diaphragms: f/5.6 - optimal for the level of softness of the created image and f/4 - giving a softer image.
The monocle is popular due to the diagonal rays appearing in the photo at a certain orientation of the camera relative to the sun.