MC W.Rokkor - SI 1:2.5 f=28mm

We know one version of the 28mm 2.5 MC-Rokkor:

The first version is based on the typical MC Rokkor style with the aperture ring in rear position. The aperture number can be seen in a viewfinder with aperture-read-in function. Little less than it's successor, the 28mm 2.5MC-Rokkor, it has a visibly warm color reproduction, that restricts it's color photography capabilities relevantly.

This model can be found moderately often on the second hand market.

MC W.Rokkor - SI 1:2.5 f=28mm Version 1
Focal length: 28mm fix
Aperture range: 1 : 2.5 - 16
Aperture type: Automatic iris, 6 blades matte.
Optical design: 9 elements / 7 groups
Detailed optical design, front to mount: 5 elements / 4 groups
- aperture -
4 elements / separate.
Close-up distance: 0.5m
Filter size: 55mm
Shade type: Screw-in type.
Length from mount plane, focus at infinity / close-up: 61mm / 66mm
Diameter: 64mm
Weight: 327g
Lens coating: Single coating, yellow-purple complementary. One green layer.
DOF type: Wheel-shaped lever.
Supported aperture functions: Stopdown metering: Yes.
Automatic diaphragm: Yes.
Meter-coupled TTL: Yes.
Aperture read-in: Yes.
Supported camera modes: M, manual: Yes.
A mode: Yes.
S mode: No.
Program mode: No.
Front view:

Polished silver front.
Rear view:

Silver ring on black mount.
Detail 1:

The DOF lever is wheel-shaped.