This is a post in a series which I've written to show sample pictures obtained with inexpensive vintage lenses fitted to a modern digital camera. In this case the lens is a Pentax-M SMC 28mm lens fitted to a Pentax K5 DSLR.
I bought this lens as part of a kit with a Pentax Program A camera a few weeks ago. Since I only paid a few pounds for both the camera and the lens I think it certainly fits into the 'inexpensive' bracket. The lens is a manual focus, K mount lens with manual aperture which covers the range of f/2.8 to f/22. The aperture itself is made up of 5 blades.
The original purpose of the lens was to provide a wide angle view on a full frame 35 mm camera, but on a crop sensor camera like the K5, the focal length is the equivalent of 42 mm which makes it a slightly wide, standard lens. It's particularly suited to Pentax DSLR's because of the K mount, but can also be used on many mirror-less cameras with a suitable adapter. The lens is coated with Pentax's SMC coating, which was reputed at the time to be very good, and Pentax prime lenses also have a reputation of being good performers.
I found that reputation to be well-founded, and consider this to be a good lens. The pictures below show the pictures I got during a couple of days walking about and although not photographically special, they do show nice contrast, colour and definition. The only slight issue I had was that I didn't always get the focus spot on, but that is more because I was relying on optical focus - I think I would have done better with focus peaking on my NEX 6.
Each of these pictures were imported into Lightroom where they had a minimum amount of post-processing, following my usual workflow.