john lucas
Darin great job. I'll just add an occasional thing. Shutter speeds also control camera sharpness. When you hand hold your camera there are will be a certain speed that the shutter simply stays open too long to get a sharp photo. this varies a lot depending on how steady you are and the magnification of the lens.
What I learned in school was the shutter speed should not be shorter than the focal length of the lens. For example you should not shoot a 135mm lens at a shutter speed less than 135 of a second. In real life and with the advent of smaller sensors in digital cameras this is no longer true.
What you should do is run a test. Shoot your camera at different speeds with different focal lengths and figure out what the slowest shutter speed is that you can shoot before your images become too soft. This will vary tremendously based on the final size of the image as well as camera shake and focal length. Just a ball park standard is, if your below 1/60 second you probably need a tripod. If your zooming in real close you probably need to use 1/125 or 1/250.