Thank you all for your help yes you ae right it is in fact a F2, a bit misleading when it says M 1:2 on the lens. Well you learn something new each day.
I will give it a go and see how it goes.

I'am awating delivery of my K10D with 18-55 kit lens. I have also purchased a FA 50mm 1.4 from the internet.
I also spotted a SMC 50mm M F1.2 on the internet for the princely sum of £25.95 which I could not resist, ,
I am know wondering what metering functions will work in the manual mode ?, and will I get a manual focus indication with this lens.
I've always wanted a fast prime hope I made the right decision.
I have just joined the forum and looking forward to being involved.
Thanks for any info.