I have created multiple exposures in-camera for many years, originally using film in an Olympus OM4. This was definately a good way to waste a lot of film!, but I enjoyed the results and created some good pictures.
Creating multiple exposures digitally in the Nikon D300 is of course much better as I can see the result on the back of the camera immediately and adjust the next exposure if necessary. It is also easier technically, as the camera will automatically calculate the correct exposure for the number of exposures selected. A far cry from film days, when forgetting to reset the underexposure adjustment could mean a lot of very underexposed frames.
All photographs are copyright to Martin Addison FRPS