Last night, I did a few experiments taking pictures with a 15 second exposure using the Canon PowerShot A75 that my dad gave my wife and I for Christmas. Here are two of the resulting photos.
This is a view of my neighboor's yard that's visible through my living room window, and is the scene that got me thinking about trying some night photography. Their porch light is casting shadows of the railing on the snow.
One thing that initially surprised me upon looking at some of the other night shots I took is that the camera saw much more color than my eyes. It only took a moment to realize that that was because the camera sees light differently than human eyes. In low light, humans see light primarily with the rods in our eyes (which aren't involved in color vision), because they're much more sensitive than the cones, which give us our color vision. The camera, on the other hand, uses the same color-sensitive sensors(*) to see the light no matter how dim the lighting. Thinking about this again a moment ago, it made me wonder why my video camera doesn't see color as richly in low light. My guess is that, because the video camera doesn't have the luxury of a 15 second exposure, it has to amplify the signal coming from its sensor in low light conditions, and that when it does that, it doesn't dare trust that it got the color quite right, so it outputs a relatively monochromatic image.
Here's a scene from in front of my house. You'll notice that a car drove through the left side of the shot, leaving three streaks of light from its headlights and ... whatever that orange light is called. It's kind of exciting to know that I now own a camera capable of doing cools shots like this. I'll have to take it to a higher traffic area some night soon.
* Technically, the sensors aren't color sensitive. Instead each little sensor has a red, green or blue filter in front of it, and the camera combines the signals from nearby sensors to figure out what color of light it's seeing.