Here i wish to demonstrate the different in longtime exposures: the natural way either by choosing "M" or the classic "B" setting - which means you simply keep the shutter of the camera open for the time of you liking.

The second is the (mainly in Olympus and Panasonic cameras) - called Live Composition or "Live Comp". Here only the highlights are registered / exposed into a first main average exposed photo. This way, at night, you can never overexpose the image, because it doesn't register the shadows. You can keep the camera shutter open as long the battery lasts (e.g. several hours). Very useful for star trails. But you can of course do/expose for other things, like lightning strikes, clouds etc. Albeit the results sometimes gets a bit odd - kind of unsettled due to the threshold between shadow and brighter areas look in my eyes unnatural.

In order to demonstrate the difference, i show you a couple photos made with normal "B" vs "Live Comp".