smc Pentax-K 55mm f/1.8
The SMC-K Pentax 55mm f/1.8 is another standard normal focal length lens that was sold as part of a kit with some of the first K-mount film cameras. Like all lenses in my collection, this one is fully manual with an aperture ring and manual focus ring. I picked it up bundled with the K105/2.8, which will be the subject of the next writeup.
Normal focal length are officially described as anything between 43mm thru 58mm, or any focal length that produces a field of view that would be "natural" for the average observer. I guess it could have been called a "natural" focal length, but I guess they are all natural, aren't they? 55mm is at the upper end of what's considered "normal," but in use feels about as normal as a 50mm. There is, however, a distinct difference in feel between 40mm and 50mm, but that's for another day.
The lens is 221g (0.5#) and, focused at infinity, 39mm long (1.6 inches) and has 6 aperture blades and 52mm filter threads. The fast aperture of f/1.8 is about average for normal lenses of the day, although some were considerably faster. The lens bears the usual aperture ring and has a rubberized grip for easy manual focusing. Minimum focus distance is 45cm (18in) producing 1:5.9 reproduction ratio (0.17x), which is pretty good unassisted. Of course, extension tubes and diopters can greatly increase the magnification.
Three photos are presented for your perusal. Above, a lonely still life of Douglas, the second tier pet of the house. He is a stuffed piece of marketing bullshit from our employer that we stripped of all identification (except his tail/tag which bears his name) and was given to Wesley and Kawai. We thought he'd be torn to shreds in minutes, but both dogs lovingly take care of little Douglas, carrying him around the house, snuggling with him, and grooming him believe it or not. The aperture on this shot is f/1.8, focused on his face. The transition to bokeh is quite slow in this shot.. maybe next go-round I'll look for something more detailed.