Focusing Unit for Long Focus Lenses

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production year 1964
type 1 (prototype?)
no serial number
no «Nikon» and no «JAPAN» marking
88mm screw-in lens mount (P=1.5mm)
revolving tripod socket with small ribbled clamp screw
no window near the aperture coupling lever
distance scale plate for 400mm lens head, calibrated in meters only, focusing range ∞ to 5 meters (16 ft.)
apertures 4.5 to 22
9 iris blades
bayonet fixed by 5 slot screws
F NKT-logo rear lens cap
shoulder strap, black
matches NIKKOR 400mm f/4.5 No.400113