Lens: Nikkor 5 cm f/2 S non-AI ('59-'63)
This sample circa '62.
Filter size: 52mm
Close focus distance: 2 feet, 0.6 meters marked.
Aperture range: f/2 - f/16
Aperture blades: 6 (early samples have 9)
Depth of field scale for f/4, f/8, f/11, f/16, and IR focusing index.
Design: 7 elements in 5 groups
Comments: This is a very early F mount lens and has a slightly unusual design to get the necessary retrofocus for the mirror box. The later 50mm f/2 H is much more common, cheaper, and a better performer. I think it is safe to say that is the better lens for most people unless you are a collector or like lenses with character like me. I like the slightly soft, lower contrast look with just a hint of swirl it gives.