As I still dabble in both :43: and Pentax worlds, I have a Rikenon 50mm lens that serves decently well. I had hoped for a deal on the -A series from Pentax though, which has the electrical contact to provide aperture feedback to my k-x. The 50mm SMC-A lenses are prized though (other than the indifferent f/2), and therefore not cheap... so I decided to go another way. Their old 35-70 f/3.5-4.5 has a good rep, not up to the fixed f/4 praise but still good. Better still, the f/3.5-4.5 weighs 240g and takes 49mm filters (I have the step ring so filters for my 14-45 and 45-200 will work), whereas the f/4 is 100g heavier and takes 58mm filters. So the 'lesser' lens fits my needs & current kit better, and keeps a few dollars in my wallet/bank. I'm looking forward to its arrival next week, for both the k-x and GH1! We'll let you know, and add a new section to the adapted-lens gallery soon! If anyone has some experience with this on their :43: kit, I'd like to hear of it - though it's mine in any case so be gentle..