Thanks for the reply's guys.
I finally got my adapter but couldn't really try it out as its been very cloudy here for the past week and will be for another few days.
However I took some pics inside with it and the photos were very dark. I did end up realising that the aperture is operated with a lever and my camera has no way of adjusting this.
The lens does not have an aperture adjustment ring on the outside either. So I resorted to some blutac against the lever to hold it open.
Now my question is this. The lens is 18-200mm f3.5 - 6.3. If I hold the aperture wide open and zoom the lens to 200mm. What is the f# it will be operating at? is it going to be f3.5?
I'm assuming the lens was manually adjusting the f # when you adjusted the zoom on the proper pentax body.
I know trial and error is going to be required to find what works, but is the above basically whats happening if I open the aperture fully and use max zoom?