Prior to 2007, I was shooting with film. One of the things I liked to do when shooting film was using a technique called "Double Exposure" or sometimes called multiple exposure.
Basically, this is when you expose the same frame of film more than once. To do this, you would set the camera up so that it does not advance the film after the first exposure. Most mid-level to advanced film SLR camera bodies had this function. Most were able to be set from about 2-9 exposures.
Mostly I liked to do this technique at night when shooting scenes with the moon.
If you ever tried shooting a scene at night with the moon, you will know that the moon blows out (over exposes) looking like a small white circle with no detail. Thats because the bright moon requires much shorter exposure time than would the rest of the scene you were shooting. If you were to expose for the moon, then you would have pretty much a dark and way too underexposed photo. Also, the moon would usually be very small as you are using a wider angle to capture the rest of the scene for the image.
Double exposing would allow me to get a larger moon that was properly exposed with some or all detail intact.
First, I would compose the scene in the viewfinder making sure the moon was not in the frame but leaving space in the composition to later expose the moon into. Exposing properly for this scene, I would focus and make the first exposure. Now, while the camera is standing by waiting for the next exposure I change lens to a longer focal length, zoom into the moon and place it in the frame where I left room for it in the previous shot. focus and expose. The moon records onto the film in the area I had left open for it, but the rest of the sky being dark records nothing over the previous scene. So, the result is a well focused and exposd moon in a well focused and exposed scene. Thats it. It does take a lot of tries and experimenting to achieve a good consistency with this technique but it is much fun a rewarding.
Sure, today I can just take another photo of the moon and then digitaly composite it into my photo later (which I have never done so far since shooting digitally) but it would just not be as exciting and does not give you the same sense of accomplishment as it did doing it with film.
So, here are a few examples of images I have shot using this technique.
Moon over Brooklyn Rooftop
Moon over marina 2
Moon over marina 1
Moon over marine Parkway bridge
Moon over steel
Moon over stone, Brooklyn Bridge
Moon over Marsh
And no one was there