Not a review quality post, so I thought I would put it here.
Picked up this SMC Pentax-M 135mm F3.5 on eBay back in October of 2012 for $22. I haven't used it much since then and it's been stored with a few other old primes. Came across it again yesterday and thought I'd slap it on the K3:
After having used primarily my big, heavy Sigmas, I did chuckle a bit at how diminutive this looked on the K3, especially with the grip.
Only had a chance to get a couple shots off before my son's friends came over to work on a school project, and I needed to feed them.
As
reviewers have noted, the lens is slow (3.5), tends to be a touch soft wide open (such as it is), and needs a little help in the contrast department. But, it's still fun to play with. I dig the built in sliding hood too. Solidly built, all metal.
Couple samples:
1/20s, F3.5, at ISO 800 hand held
1/60s, F8 (I think), ISO 6400 handheld