ZM-5SA (3M-5CA) russian mirror lens
Focal length : 500mm
Maximum aperture : F8 ( FIX)
Overall dimension : 83 x 139 mm
FILTER : 72mm
Weight : 0.620 kg
Min focusing range : 4 m
this lens was the lightest russian mirror lens , since the weight is 0.620 kg it's working pretty well with my olympus E3 . (There are some photo i took by E3 without out tripod in the bottom).
This lens was made by Muksutiove mirror optics (russian factory in Lytkarino). It's said to be buid around 1984. 3M-5CA was redesign from fomer lens 3M-5A but cutting some weight ( 3M-5A weight = 1.225 kg) buy cutting of tripod collar and also build in hood. But with same quilty built of lens some said it's have better code. Also in russian web site siad that these lens was next generation MTO.
some of the picture was pross process with lil sharpen