i just ordered that bad ass lens. it's my second da* lens, which is the pro series from pentax. full weather sealing, internal sonic focus so it doesn't rotate the front element or change shape. it has sick mtf benchmarks too.
this is my lens for the year. next christmas i'm thinking i'm due for a fast wide prime like the 31mm f1.8 limited.
my new mobile kit with by my 16-50/50-135/135/(rotating spot).