Spencer 7x50 Mark 30

Mfr: Spencer Lens, Buffalo, USA

Date: WWII

AFOV: 54 degrees

Eye Relief: 14.5mm

This model has a slightly wider field of view than the usual American 7x50 from WWII (most have an AFOV of about 50 degrees).  This results in a noticeably more pleasing view.  The body is also more rounded and comfortable to hold than that of the usual 7x50.  Shown below is a Mark 30 Mod 1.  I am not sure what the difference is from a Mark 30 Mod 0.

A Mark 30 prism cluster is shown below.  The two prisms are not the same size.

Top prism:  29mm x 57mm x 27mm high, not grooved or shielded.

Bottom prism:  23.5mm x 51mm x 22.5mm high, grooved and shielded.  Since the back of this prism faces the objective, the shielding protects against stray light.  A groove between the entrance and exit faces (on the long side) is supposed to cut off stray light beams along the edge.