I-26m-U 2.8 / 52 (INDUSTAR-26M-U F / 2.8 52 mm) - a lens for Soviet magnifiers. The lens does not have a focus ring, which makes it difficult to use as a photographic lens. I-26m-U 2,8 / 52 can be easily turned into a macro lens, which, in fact, is what makes it interesting.

The I-26m-U 2.8/52 is a reworking of the Industar-26m 1:2.8 F=5cm P/I-26m 2.8/52 lens (or the like) for use in photo enlargers.
It differs from the hordes of other similar lenses of the I-50 / I-96 series for I-26m-U 2.8 / 52 enlargers in its body, relative aperture, as well as a 10-blade aperture, which closes to a minimum value of F / 16.

On Canon cameras, you can use a lens with two adapters: M42-Canon EOS + M39-M42.

On Nikon cameras, you can use a lens with two adapters: M42-Nikon F + M39-M42.

I-26m-U 2,8/52 does not have a focusing ring. Focusing with this lens in the usual sense of the word is impossible. The lens is always focused at a certain distance. It is very convenient to focus by moving the camera towards or away from the subject. It is very convenient to use the I-26m-U 2.8 / 52 with macro rings of different thicknesses, which allows you to change the focusing distance and the magnification factor.