smc Pentax-K 24mm f/2.8
Twenty-four millimeters is apparently not a popular focal length among Pentaxians. I say this because only four 24mm lenses were made by Pentax since the introduction of the K-mount, and at Pentax Forums, all four have mediocre ratings. This Pentax SMC-K 24mm f/2.8 is virtually identical to the A-series lens, and has no M-series counterpart.
The lens is 41.5mm long (1.6 inches) and 194g (0.4#) and has 52mm filter threads. The lens handles like all other Pentax manual focus and manual aperture lenses, which is to say it's solid, smooth, and compact. This is not a lens I reach for very often, because it never seems to hit the spot I'm looking for. Then again, I choose my lenses by a randomization process, so I rarely allow for breaks from that procedure and avoid taking control of lens choice.