I need one that has a ridiculously short lag time, not a lot of shake, great zoom, works well in the dark (I'm taking it to a concert), it has to be compact, and under $200. Does anyone have any suggestions?
Thank you for sharing your dream with us. Too bad that dreams so seldom come true. Not only does concert photography demand rather specialized equipment, it also requires a lot of skill. (Been there, and have the album covers to prove it.)
Anticipation, and knowing your subject can overcome any lag time. It is just a matter of practice to develop a feeling of the time needed to lead ahead of the peak of action. Look for a camera with image stabilization - hand-holding a very small camera is extremely difficult. Larger, heavier cameras have enough surface and mass that your heartbeat does not cause blur. Panasonic I believe, does offer stabilization at the lower end.
Stages are quite well lit for the most part, unless you intend to photograph the audience. However, there is often a great deal of contrast, so it is easy to blow out all your highlight detail. Any time the light or angle changes, do a test shot and use exposure compensation to fine tune your exposure. That is what the monitor on the back of the camera is for. Stage photography is extremely challenging to automatic metering systems.
Many of the cameras in this price range offer high ISO settings, but due to the tiny sensors, must use extremely aggressive noise reduction. This can result it such a loss of detail, that the photo will look more like a painting. In many cameras, you have no control over this, so you just have to live with it.
My recommendation is to start out looking at Panasonic, since image stabilization seems to be standard with their line. Whatever, you buy, get it well before the concert and work through the manual so you are completely fluent with the camera and have had time to do a lot of practice. Constantly check results on your monitor. The major goal of the practice is in being able to see where there are problems and knowing how to correct them. I do have some more tips on how automatic cameras can trip you up at