Released in 1964, the Olympus Pen D2 was the second in the D series of half-frame cameras that began with the Pen D (1962) and concluded with the Pen D3 (1965). The D series were designed to be more professional half-frame cameras with greater exposure control, built-in light meters and a fast, sharp lens.
The Olympus Pen D2 updated the selenium light meter of the original Pen D with a battery-powered CdS meter. The CdS meter was a better performer, especially in low light, and more reliable over time. It was uncoupled with a meter display on the top of the camera reading out in EV units that were then transferred to the exposure ring on the lens to set shutter and aperture. Speaking of the latter, the camera has a leaf shutter with speeds ranging from 1/8 to 1/500, plus a Bulb mode. As mentioned, the lens has a fast f1.9 maximum aperture with a minimum f16 aperture possible. The user is free to adjust both of these manually and both are entirely mechanical - only the light meter was dependent upon battery power. Focusing was done via a zone system with distance markings on the lens barrel. The Pen D2 is a viewfinder-style camera, lacking a rangefinder as focusing aid.
As one would expect of Olympus, the F.Zuiko 32mm f1.9 lens is quite sharp. Olympus prided themselves on making good optics and the lens on the Pen D2 upholds that tradition quite well.
At the risk of having buried the lead, it is worth noting in closing that the Pen D series are all half-frame, producing 24x18mm frames for a whopping total of 72 pictures on a standard 36exp roll of film. Half-frame cameras offer the obvious advantage of film economy (at the expense of a smaller frame size) but also a lot of labs (like yours truly) are able to print or scan a pair of half-frame negatives together in a single frame allowing for creative diptych pairings.