To start with, you’ll need to locate the dial on the top of your camera, with letters written on it. This dial will always include, at the very minimum, these four letters — P, A (or AV), S (or TV), and M. There will also be a fifth mode entitled Auto. Let’s look at what these different letters actually mean.
Auto Mode
This mode pretty much does exactly what it says on the dial. In Auto Mode, the camera will set everything for you — from your aperture and shutter speed right through to your white balance and ISO. It will also automatically fire your pop-up flash (if your camera has one) when needed. This is a good mode to use while you familiarize yourself with your camera, and it is particularly useful if you need to photograph something quickly when you don’t have time to set the camera up manually. Auto mode is sometimes represented by a green box on the camera dial.
Program Mode (P)
Program Mode is a semi-automatic mode, and it’s sometimes called Program Auto mode. The camera still controls most of the functions, but you are able to control ISO, white balance, and flash. The camera will then automatically adjust the shutter speed and aperture settings to work with the other settings you’ve created, making this one of the easier advanced shooting modes you could use. For example, in Program Mode, you could prevent the flash from firing automatically and instead raise the ISO to compensate for low light conditions, such as when you don’t want the flash to wash out the subjects’ features for an indoor photo. Program Mode can really add to your creativity, and it’s great for beginners to start exploring the camera’s features.
Aperture Priority Mode (A or AV)
In Aperture Priority Mode, you have control over setting the aperture (or f-stop). This means that you can control both the amount of light that comes through the lens and the depth of field. This mode is particularly useful if you’re concerned about having control over the amount of the image that is in focus (i.e., depth of field), and are photographing a stationary image that won’t be affected by shutter speed.
Shutter Priority Mode (S or TV)
When trying to freeze fast moving objects, shutter priority mode is your friend. It’s also ideal for times when you want to use long exposures. You’ll have control over the shutter speed, and the camera will set the appropriate aperture and ISO setting for you. Shutter Priority Mode is especially useful for sport and wildlife photography.
Manual Mode (M)
This is the mode that pro photographers use most of the time, as it allows complete control over all the camera’s functions. Manual mode means that you can adjust all functions to suit lighting conditions and other factors. However, using Manual Mode requires a good understanding of the relationships between different functions — in particular of the relationship between shutter speed and aperture.
Scene Modes (SCN)
Some advanced DSLR cameras are beginning to include a scene mode option on the mode dial, usually marked with an SCN. These modes initially appeared with point-and-shoot cameras, attempting to allow the photographer to match the scene he or she is trying to photograph with the settings on the camera, but in a simplistic manner. DSLR manufacturers are including scene modes on DSLR camera mode dials to try to help inexperienced photographers migrate to the more advanced camera. Scene Modes can also help budding photographers learn the capabilities of their camera.
