Came across a good condition Pentax 110 recently and although I'm not into collecting vintage camera gear, I was prepared to keep this one for the timeless looks and its unique place in photographic history. It is such a cute camera that I wish Pentax would re-issue a modern digital version.
Briefly the Pentax 110 was Pentax's smallest SLR camera, and the smallest interchangeable lens SLR with TTL metering ever made. The camera has a proper TTL viewfinder, split image rangefinder focusing, programmed auto exposure using a center weighted metering silicon photo diode with shutter speeds from 1 sec to 1/750th, an exposure range of EV 3 to 17 at ASA 100, with an aperture range from f/2.8 to f/13.5. There were 6 lenses available, and the 24mm f/2.8 standard lens shown here (equivalent to 50mm on 35mm film) has a very smooth focusing ring with distance scales, has 6 elements in 5 groups, focuses down to 0.35m and weighs... a mere 13 grams!
The small format means that the camera has a lot of depth of field and is almost like a modern 4/3 format digital camera with a 2x crop factor. In fact the lenses have been modified to fit some current micro 4/3 cameras. The issue of usability with this camera is hampered by the limited availability of 110 film. Nonetheless this camera continues to marvel many even today.