After playing with my D5000 for a while I wanted to try some manual settings. I took some photography classes in college so I knew the basics. How the aperture and shutter speeds effected the exposure. I was in the dark on how to work with the automatic light meter. In auto mode the the settings are all over the place. Even the film speed was running all over the place. This gave me the idea to go back to basics. So, I borrowed a friends light meter. This would give me an exposure I understood and could use to take a photo. Once i had a meter reading I could set my cameras exposure. Then get a much better feel for what the camera was doing.
Auto is for amateurs
When I set my DSLR to auto exposure I feel like I gave up. It's super easy, but the camera is in control. Great photos are rarely easy. I want to have control of my photos especially the exposure. Using a stand alone light meter gives me great info to base my exposure on. Once I take a reading of the light available I can choose how to use it.
"bad" exposures can sometimes be good.
Your cameras auto exposure does a great job of making an even flat exposure. The reflective meter in your DSLR reads the light coming into the lens. Then it tries to use that reading to set the exposure of your photo. The computer in your camera will try to average out the light and dark areas. Basically trying to make the whole photo exposed for neutral grey.
This photo was shot with auto exposure
This one was shot with manual exposure
and metered with an indecent light meter
Increasing the exposure beyond average lets us see detail in the child's face. The camera thinks this exposure is wrong, but we can see the result correct.