AE memory lock. Why oh WHY did Pentax leave this off almost all their auto exposure cameras? I think the very late P30 has it, but then it is DX code only with no override, which is worse.
This lack is the one thing that prevents my LX from being the absolutely superb machine it should be and otherwise is. Even my Ricoh XR-7 has it. I have to get around to replacing the light seals on that camera. It's a lightly built consumer grade mainly plastic camera but it's so well thought out I just love shooting with it.