Typically, point-and-shoot cameras have a few “scene” modes which allow users to take better pictures in special occasions. Today, we will try to figure out what the camera does in each of these scenes.
Portrait - in portrait mode, camera will try to make the background as blurry as possible (so viewer will pay attention to the person). To make background blurry, it will open up the aperture (hole) as much as possible to decrease depth of field (DOF). Typically, the camera will use the maximum aperture value of the camera. Here is an example of a picture with blurry background equivalent to portrait mode (f/1.8).
Landscape - in landscape mode, the camera will do the exact opposite of portrait mode: it will try to make everything as focused as possible. To do this, it will close up the aperture. Typically, it will use the smallest aperture (biggest F number) while keeping shutter speed above 1/30 (cause less than 1/30 will capture blurry picture from hand shake, remember?). Here is a sample picture with equivalent landscape mode where aperture is closed up (f/8 ) to make everything focused.
Sports - in sports mode, the camera needs to “freeze” something that is moving fast. To do this, it needs to make shutter speed as fast as possible (for example 1/125 of a second). Therefore, it will try to set the shutter speed to a fast value while keeping aperture to a reasonable setting (such as f/8 ) for easier focus. Here is an example where the motorcycle is “frozen” (f/22, 1/200).
Night Landscape – for example, city lights only (no foreground person). Camera will increase ISO sensitivity to highest value (for example, 800), then balance both aperture and shutter speed. Typically, you will need a tripod.
Night Portrait – for example, portrait in a dimly lit restaurant. The goal is to use flash to light the person, yet capture the background in it’s original lighting. To do this, camera will keep shutter speed about 1/30 of a second, open up the aperture (small F number), and fire the flash to lit the person. This is an example with shutter speed of 1/60 and flash on.
See, it’s really not all that complicated once you understand how to expose the sensor. Science rocks!