Over the years, the best analogy I’ve found to describe Proper Exposure is a full bucket of water. Using a garden hose will take a long time to fill the bucket. But using a fire hose will fill it in a fraction of a second. Same end result.

Your Aperture is like the hose. Your Shutter Speed is the time it takes to fill the bucket of Proper Exposure. A small Aperture of F11, 16 or 22 will require a longer time (slower Shutter Speed) as opposed to a large Aperture of F1.4, 2 or 2.8 needing very little time (fast Shutter Speed) to get the Proper Exposure.

Remember that each step in Aperture or Shutter Speed will halve or double the amount of light. For any given picture there are a number of combinations that will work. Shooting at 1/500 and F8 or 1/250 and F11 or 1/125 and F16 or 1/60 and F22 will all result in the same amount of light hitting the film. The difference will be in how much Depth of Field you get and how well action or movement will be stopped. It’s up to you to decide which is best for the subject matter you are shooting.

I know that for some people this is heady stuff. It took me a while to understand it all. Once you get a good grasp of how Aperture and Shutter Speed change how your pictures look, you’re on the way to creating images the way you see them in your minds eye. Be patient Grasshopper! As I cover Exposure Modes (P,A,S,M) during the next few days all of this will become clearer.

Would you like to have a complete understanding of Exposure? You’re in luck. Bryan Peterson has written a comprehensive book on just this subject. Check out his book Understanding Exposure right now.