A large number of lenses is well-known under the name «Helios-81″. After the collapse of the USSR the Arsenal plant (in the territory of Ukraine) has continued to make the «Soviet» lenses, but has changed their designation to «ARSAT». So, many Soviet lenses have two names.
They say, Arsat H 1:2 50mm is just the second name of the legendary lens MS Helios-81H 2/50. But in practice it isn’t so.
- Arsat H 1:2 50mm has a rubberized focusing ring, MC Helios-81H 2/50 — metallic.
- Arsat H 1:2 50mm is an AI lens for Nikon cameras, MC Helios-81H 2/50 is not an AI-lens. My MC Helios-81H 2/50 has an opportunity to transmit aperture’s value to the camera through a aperture’s rheostat, but it rests the skirt against the EE lever of the cameras Nikon D100, D50, D70, D70s, D80, D90. It means that Arsat H 1:2 50mm can be set on any digital-reflection Nikon, and the MC Helios-81H 2/50 can’t be set on 6 cameras, without preliminary «subfile» of a skirt in the place of a contact with the EE lever.
- Different aperture’s blackening. Arsat’s H 1:2 50mm aperture blades are blackened much better, than MC Gelios’s-81N 2/50. Aperture blackening influences rereflection of light by the shooting on the covered apertures.
- Different years of release. The lenses Arsat H 1:2 50mm are newer and that increases chances of their normal preservation.
By the comparing I didn’t notice any differences in pictures quality between these two lenses. But Arsat H 1:2 50mm wins because of rubberized focusing ring, an opportunity to be mounted on every Nikon cameras and the best blackening of aperture blades.