Originally posted by ripper2860 I own one and can say that it ranks as one of the most highly regarded 135mm lenses in the Pentax stable. A very lovely piece of Multi-coated glass rendering delicious colors and bokeh.
Yes, indeed. And, interestingly, the K 135/2.5 shares the same 6-elements-in-6-groups design with two other highly regarded telephoto lenses -
K 135/2.5
K 200/2.5
A* 200/2.8
Of course, the newer A* 200/2.8 does use ED glass for a couple of elements, but the similarites are, I think, striking.
And, I should also point out that the SMC K 135/2.5 is ~not~ the same lens as the non-SMC, 4-element-in-4-groups "Takumar 135/2.5 [Bayonet]" consumer lens. On the contrary, the SMC K 135/2.5, such as being sold here, is certainly one of the best Pentax lenses.
[The images are from Boz's ~excellent~ K-mount site -
Welcome to Bojidar Dimitrov's Pentax K-Mount Page ]