F-3 telephoto anastigmat Soviet lens

Description

Objective "F-3" f = 4.5 / 400 mm. - a five-element telephoto lens-anastigmat (Fig. 1) of average aperture. The objective lenses are chemically coated.
The lens is designed for photo control devices operating on 35 mm film with a frame size of 24 × 30 mm.
A large focal length, relatively high aperture ratio and a large aperture range allow the lens to be used for shooting distant objects under various light conditions.
The lens is framed in a special frame (Fig. 2). The frame has a diaphragm ring with a scale. The lens aperture in the range from 1: 4.5 to 1:45 is performed by rotating this ring. The aperture value is read on the scale against the index. The aperture in the lens is iris.
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