I believe this is my first post since signing up last year. i have a Pentax K30 and I'm after a prime lens. 50mm primes are in abundance on eBay but not so much the longer focal ranges like 100mm, 135mm etc. im basically confused on mounts as most don't state the mount version. A lot are PK but I don't know if that fits K-mount, M42's are screw mount so won't fit without an adaptor and I mostly see smc Pentax-m?!. I don't know what to go with, I want to do landscapes and macro more as I've mostly done abandoned buildings. i already have the 18-55 and 55-300 lenses and the cheap (for funsies), close-up lenses but I'm ill and the weather is crappy so I'm yet to find the personal drive to try them out.