I was out with the Pentax f1.4 50mm manual lens today. I was very happy with the results, considering the age and manualness of the lens, I thought they were pretty good and the fast aperture is a real boon. I think the image quality and clarity is better than any of the zooms I have at 50mm (if the focus and shake are up to scratch). I have a 24mm f2.8 manual lens as well, I think I need to try out that one next time. Not as fast as the fifty, but I think I need to explore it a bit.
It is pretty easy to adapt a manual lens to work as an auto aperture one. You only need to add the contacts to short out the ‘A’ sensing on the lens. With nothing else, the f1.4 is recognised as an f1.2, or you can add the necessary insulators to make it work properly. I had a fiddle with adapting the 50 to auto aperture. I have drilled the hole on the lens mount, but chickened out of drilling down to get a contact in. When it came to doing something permanent, I decided that the ‘press button for setting the exposure’ before taking the photo is not that bad after all!