The MC APO Telezenitar 300 mm f/ 4.5 (Russian: "АПО Телезенитар") is an interchangeable telephoto lens for 24×36 mm cameras with 45.5 mm flange focal distance. It is equipped with an instant-return aperture and a telescopic hood.
There are two variants of the lens:
"К" indexed for cameras with the K bayonet mount;
"М" indexed for cameras with the M42 screw mount.
As opposed to the APO-Tair-1 300 mm f/ 4.5, the optical scheme of the lens employs special sorts of optic glass with properties very close to fluorite, thanks to which its price is reduced and reliability is increased.
Focusing is performed by moving optical member and internal optical scheme elements, which made it possible to slightly increase the lens length when shooting at the closest distance.
resolution (center/edge): 60/ 35;
angle of view: 8º;
coefficient of transparency: 0.87;
color contribution index (CCI): 13-0-(-1).
The MC APO Telezenitar 300 mm f/ 4.5 was produced and is produced (?) in small batches at the KMZ (S. A. Zverev Krasnogorsk Mechanical Plant).