I was doing some photography for a community theater yesterday and was talking to one of the board of directors about using a camera. She said that she had purchased a Canon Rebel a couple of years ago, but had bought a point and shoot last year because she didn’t understand how to use the Rebel. Her quote was “I just put it on the green auto and then I don’t know what to do. Why carry a big camera when a small point and shoot will do the same thing?”
After some further discussion I figured out what she meant was that she didn’t know how to use the camera to utilize the features of the camera. She didn’t understand the relationship of the exposure triangle; shutter speed, aperture, and ISO. There have been plenty of books written about exposure, so I’m not going to go into it here. I will address how to wean your way from auto to full manual.
The first step is to GET IT OFF THE GREEN AUTO. But where to?
Start with the Program setting. It’s the same on Canon and Nikon cameras: P
Program is basically the same as the Green Auto, but you have some control over it. The camera’s computer evaluates the scene and picks the best settings to get the correct exposure. But you can change the settings; usually by changing the shutter speed. As you change the shutter speed, the camera changes the aperture to maintain the correct exposure. If you are looking through the view finder and watching the numbers at the bottom, you will begin to see that as you slow the shutter speed down, the aperture number gets bigger.
That is because the longer the shutter is open, the more light is let in. To compensate for that the camera makes to opening in the lens smaller. Likewise, when you use a faster shutter speed, the aperture numbers will get smaller because the opening of the lens is getting bigger.
If you experiment with the camera on P, changing the shutter speed and watching the aperture change, you can begin to get a feel for how the camera is thinking as it evaluates the scene in front of it. When you are doing so, take lots of pictures and start to look at how the images are effected by each change.
Once you feel comfortable with changing the settings on the Program mode, try Shutter Priority (S on Nikon and Tv on Canon). Again, watch the aperture settings in the viewfinder as you change the shutter speed. Remember, as you slow the shutter speed down, you will begin to see motion become blurred in the image and as you speed it up, motion begins to take on a stopped look.
You can also begin to experiment with Aperture Priority (A on Nikon and Av on Canon). Once more, watch the shutter speed settings as you change the aperture. Aperture is the setting that confuses most people. Just remember, the bigger the number, the smaller the opening, but the bigger the depth of field. In other words: if you set the aperture to f16, you are making a very small hole in the lens and letting less light through, but you are allowing more to be in focus. Conversely, if you set it to f2.8, you are making a really big hole in the lens, but you have a very short depth of field.
Think about the affect of aperture when you are taking a portrait. If you set the aperture to f2.8, your subject will be in focus, but not the background and the shutter speed will be very fast. A setting of f16 will result in everything being in focus and a slow shutter speed.
When you feel comfortable with those, try Manual. Again, its the same on both Nikon and Canon: M. In this setting, you control everything and this is where photography gets fun. Lets say you want to take a picture of a person walking. You want some blur of their hands and feet as they moved and you want to isolate them from the background. You would use a slower shutter speed (maybe 1/15) and a more open aperture (possibly f4).
You can find more about using a camera on this post at the Digital Photography School