Thats not stupid.
Of course the manual lenses are somehwat more challenging to use due to lack of autofocus and auto-exposure. I found it hard to get the focus spot on with people using the largest aperture, if I stop down a little it gets easier though. It's not for snapshots (for me at least, but I think it's a matter of training as well), but if you are willing to plan your shots a little it is very rewarding.
I use the Pentax adapter. I actually bought a third-party version from Hong Kong first, but it did not work properly. Some people say that there is third party versions that work fine. But I was out of luck I guess. :
