Build quality: good
Filter thread: 49mm
Infrared Mark: yes
Eventhough it is a rather old design, it lives up to the Pentax fame. Nothing extreme, just a well-built, sharp, small prime that can be used on the Asahi Pentax Spotmatic cameras with open aperture metering in Av mode due to its extra lever and alignment lug.
7.5ccm of mayhem, shot wide open at 2.0
Engineering modell of a Francis turbine, shot at 2.0
More shots with this lens in my Gallery: SMC_Takumar_55mm_2.0.html