Here they are at infinity focus with caps on. (L to R) K28mm f3.5, K35mm f3.5, K50mm f1.4 and K135mm f2.5. They are reasonably compact, but the 35 is just really small, making for a nice package on the camera. Would show it on the camera but I am without another camera to take a picture of my camera with....
Fully extended to close focus, still compact, though the 135 is getting a little long. It is a solid chunk of glass for sure!
And two head on. The first three have a 52mm filter thread, which makes it easy to share filters and a rubber lens hood. The 135 has a 58mm filter thread.
It is interesting to see the color difference with the 50mm coatings, there is a reddish tint to it, which I never noticed before.