Been toying a bit with how to use the C1-C4 modes on my LX5. So far I've set up C1 for low light/"action" shooting, based on Shutter priority with auto ISO on. I set the shutter speed for my intended purpose and let the camera deal with the rest. C2 is set up for "optimal conditions" Aperture priority, ISO 80, F4.5. Basicly outdoors on a sunny day, or for tripod night long exposures. I'll probably set up C3 for when I put on an external flash, not sure about C4 yet. How do the rest of you use them, if at all?