I've got a Super Takumar 50/F1.4. My copy won't focus sharply past 11m (this is with a recessed M42 adapter on a Pentax K-mount), so landscape usage is out, but there's a lot of stuff you can shoot within that distance.
This version has the white dot in the f/2 aperture ring position, so it's a late model. Some of the late models had the SMC surreptitiously applied, but I don't think this one does, so it's contrast is probably inferior to the SMC version. It would have been manufactured 1967-1970. Serial Number is 2458xxx.
The later SMC version definitely had the SMC coating, 8 aperture blades instead of 6 (you can seen a hexagonal shape in the bokeh of the shot below), and I believe that at least some of SMC versions (maybe all) had the mechanical aperture coupling lever.
This is a thoriated lens and I had to de-yellow it by exposing it to sunlight for a few weeks.
Interesting links to articles about mildly radioactive lenses are found here:
Radioactive lenses Introduction of Thorium Oxide into Super Takumar Lenses Radioactive lenses - Camerapedia (the radio-active element is the last one so there's much more radioactivity from the rear of the lens than from the front.)
Radioactive Camera Lens From The 1960's
I've had problems getting a consistent focus as I don't have a split-prism focusing screen. Anyway I've tried 10x magnification in LV on the K-5 and it works well on a tripod with a static subject.
Here's a test of focus using LV. I focused on the small dark rectangular defect near the bottom of the orange flower. The top of the blue part may look like it's over-exposed, but the top of it is very pale. Perhaps it's sun-bleached. Pentax K-5, 1/640s, f/2.8, ISO80.
Here's a 100% (un-resized) crop so you can see the focusing accuracy:
Dan.
Last edited by dosdan; 02-02-2012 at 05:40 AM.