Attention: when installed through a conventional adapter M42-Nikon F, M42-Canon EOS or any 'M42-Your System', etc., the Vega-5U 4/105 lens will damage the camera mirror, since it has a huge protrusion of the rear part of the helicoid. Check out the image of the lens in the gallery above for yourself - the rear protrudes a lot. The lens can be used on narrow format (on conventional cropped and full format modern digital SLR or mirrorless cameras) only with macro tubes or macro fur.
Note: The rear of the lens is thick enough to fit into some extension tubes. I have several sets of macro rings, with some of them this lens cannot be used for this reason.
The focal length of the lens is quite large, from about 78 to 90 mm, so it can be easily installed and used on any modern digital camera. At the same time, even on SLR cameras, focusing to infinity can be easily achieved by using the correct selection of the macro ring thickness. By changing the length of the macro ring set, you can change the focusing distance.