Lens of the USSR "Industar-61 L/Z" 2.8/50 - M42 with Screw Mount. Functionality: the lens is in like new condition - the lens elements are clean, visibility is excellent - without distortion or aberration, focusing and aperture operation is smooth and pleasant. The diaphragm blades are dry and free of excess lubrication. The deep-set glass and small opening sizes are exactly reminiscent of the Carl Zeiss Jena Tessar 2.8/50. The lens has only 4 lenses in 3 groups. Due to its excellent sharpness and design, the lens is excellent for macro photography using macro rings, which has earned it the reputation of not just an excellent standard lens, but also a macro lens. A focal length of 50mm when used on cropped matrices gives the equivalent of 75mm for Nikon (1.5x) or 80mm Canon (1.6x), which can be used as a portrait lens. Sharpness at 2.8 is excellent, but due to the small depth of field, the resulting portraits do not particularly suffer from excessive sharpness. Still, I do not recommend it for facial portraits - few people like excessive sharpness on the skin, so in the example photographs there is only nature. The lens has good contrast and resolution even at the edges of the frame (this is true on a crop matrix). Center/edge resolution 45/28 l/mm. The bokeh is plastic, but due to the design of the aperture, it seems that there is a grid in the background that has been blurred; this is not the best option for a portrait. It holds side and backlight tolerably, but not excellently. Disadvantages: 1. Small aperture. Nowadays, primes with 50mm usually have from 1.4 to 1.8 aperture, which is one stop more than that of the Industar 61 LZ. The aperture of Industar is explained by its optical design, which is aimed at achieving a sharp image, and not at increasing the aperture. 2. The number of aperture blades is only 6 and its appearance is quite strange. Among the advantages: 1. Excellent sharpness of the classic Tessar scheme, sometimes no worse and better than the well-known Carl Zeiss Jena Tessar. Provides sharpness at both close and long focusing distances. 2. Good use for macro photography (if there are macro rings). 3. Multi-enlightenment. 4. Can work with full-frame cameras for those awaiting an upgrade from cropped matrices to FF. 6. A metal structure that will outlive all of us for decades. Interesting points: A group of lenses is deeply recessed into the helicoid, which creates a kind of lens hood with stepped light traps. The focuser moves nicely, the minimum focusing distance is less than 30cm, which allows you to shoot small objects without using macro rings. The diaphragm has a very unusual appearance, which is rarely seen; in the blur zone it produces not nuts, but strange hexagons. Your parcel will be packed as securely as possible by me personally, assuming all possible risks during transportation: falling from hands, pressure from neighboring parcels from above and on the sides, rain, snow and similar force majeure circumstances. You do not pay anything for materials and packaging of goods, packaging material is at my expense, as a bonus.