I was given a Pentax ME super by my father in law, but sadly, its 50mm 1.4 Pentax SMC lens is totally eaten by fungus. This lens is a gem, I used it a few years ago and wish to buy another one. I could buy a 50mm 1.4 Rikenon too, but I don't know much about it. I need some advice from people who have used both lenses, and if you know other fast lenses at least as good as the Pentax. Thanks.