The mode dial is used to change the camera’s settings and access different shooting modes.
Mode dials will vary, depending on the make and model of camera.
Each setting is "activated" by turning the mode dial until the letter, or symbol, lines up with the "marker point," such as this white line, above.
Automatic – the symbol may be green coloured, as in the top example, the word auto and in some cameras the letter A for automatic (mode)
This means the camera "makes the decisions." This allows you to only concern yourself with aiming the camera at your subject, deciding on the composition and pressing the shutter release button to take the photo.
Aperture Priority - the symbol will be the letter(s) A or Av.
You can use it to make adjustments for depth-of-field, in other words how much of your subject is intentionally in focus, or blurred. In addition, to control the amount of light hitting your camera sensor, which affects exposure. In this mode, the camera will make adjustments to the shutter speed to deliver, as best as it can, the correct exposure and "effect" in your photo.
Shutter Speed Priority - the symbol will be the letter S or Tv (for time value).
This helps create different "moods" such as the blurred feathery effect of water with a slower shutter speed. In contrast, is the crisp clear suspended motion as you "freeze the action" with a faster shutter speed. The camera will automatically adjust the aperture to balance the exposure.
Manual - the symbol is the letter M.
In this mode, it is up to you to choose and make adjustments to the aperture and shutter speed settings for what you want the result to be. For example, depending on the way you "adjust" the settings will result in "moods being created" and the correct exposure, or light.
Bulb - the symbol is the letter B.
In this mode, you decide on the length of time it will take the camera to record the exposure, or take the photo. In bulb, the camera will continue "taking the photo" for as long as the shutter remains open while your finger holds the shutter release button down for the amount of time you decide. Or by using a cable (shutter) release accessory which, in effect, does it for you.
Flash X sync speed - the symbol is the red letter X.
The setting in this particular camera is used when an external flash does not automatically change the shutter speed.
Program - the symbol is the letter P.
The program mode will automatically adjust the shutter speed and aperture. Using the front and rear e-dials (on the camera) in this mode allows for easy switching between shutter priority and aperture priority.
Shutter & Aperture Priority - the symbol is TAv
The TAv setting automatically sets the sensitivity so that the selected shutter speed and aperture will give the proper exposure according to the brightness of the subject.