I have a Pentax ME-F -- the original autofocus Pentax. It's a nice camera but I've never got it working properly due to a simple problem. It looks like the rubber/foam on the mirror has corroded and gummed up the mirror operation. When you fire the shutter it takes 1 or 2 secs to raise the mirror up before it fires the shutter. Everything else on it works OK, the shutter speeds are fine and the metering, etc. It can actually be used if on a tripod for landscape shots, but I have no interest in an SLR with a shutter lag anywhere between 1 and 5 seconds! How easy is it to fix this, do you think? Is it worth the effort? Am I better just selling it for spares?