These are things that I know that I don't have to think about:
Exposure is how much light is exposed to the CCD
Metering is the focus on the subject and has three different modes; spot, center-weighted, and evaluative. Changing the setting on the metering changes the focus on the subject or the thing behind him.
The aperture is the thing that controls the amount of light being let into the camera. Changing the aperture changes the brightness of the photo and the amount of blur.
The shutter is the thing that opens to let in light. When changing the shutter speed, you are changing the quickness that the shutter opens and closes to let light in, then the light has to get through the aperture to the CCD chip which stores the memory of the photo.
When working on the pinhole camera, we created an aperture by putting a hole into the box or can and created a shutter with the flap of black paper. The CCD was replaced with photosensitive paper, which when exposed to light, starts developing, so we had to make sure that when we were not taking pictures, we did not let the film have any light touching it. We had it covered by paper and put it in a can until we needed to take a picture and then we lifted the flap of black paper (our shutter) and let in the light through the hole (our aperture) and let the light hit the photosensitive film.
On digital cameras, the camera automatically sets the aperture, the shutter speed and the DOF, but the user still can change them manually in the settings of the camera. When the user changes settings and screws something up, the camera can reset the settings if it is turned off then back on again. When the photo setting is on auto, the shutter, aperture and DOF are all automatically set and cannot be changed.
