Shutter Speed (Tv) is how fast the shutter opens and closes to snap a photo. The faster the shutter speed the less light that enters the camera. A slower shutter speed allows more light to enter.
Fast shutter speeds are perfect for sports photos.
Slow shutter speeds produce smooth water photos.
Shutter speed is measured in whole seconds and fractions of a second. Commonly, you will see it scaled like this:
1, 1/2, 1/4, 1/8, 1/15, 1/30, 1/60, 1/125, 1/250, 1/500, 1/1000
Depending on the type of camera you own, you may also see it only written in whole numbers:
1, 2, 4, 8, 15, 30, 60, 125, 250, 500, 1000
In this case 1 will be equal to one second and everything to the right of it equals a fraction, i.e., 1/2, 1/4 ... 1/1000.
Aperture (Av) is a set of blades inside the camera's lens that adjust to let more or less light in. Consider it comparable to the iris of a human eyeball. In a well light area, the iris constricts letting less light in to the eye. On the other hand, in a dark room the iris opens to allow more like to enter the eye.
Aperture is represented by a number scale referred to as f-stops:
f-1, f-1.4, f-2, f-2.8, f-4, f-5.6, f-8, f-11, f-16, f-22, f-32
It is important to remember that the larger the f-stop the smaller the aperture. The smaller the aperture results in less light entering the lens. The smaller the f-stop the more light that enters the lens.
For example, f-32 is the equivalent of standing outside on a sunny day; therefore, not a lot of light is entering the eye (or lens) because of the abundant light surrounding the camera.
However, f-1 would be exactly like standing in a pitch black room and your iris opening in order to let more light into your eye. An aperture f-stop this small would let a lot of light so that when the photo is taken in a dark area it will not be too black.
Film Speed (ISO) is the ability of the camera's sensor to accurately read the quality of the scene and producing pixels to match the available light. Photographs that have little light can often show noise or grain that results from too many pixels.
When shooting an action scene (sports) or outside where the sun is lighting up your shooting area, then adjust your camera to ISO 400 or ISO 800. This will limit the amount of noise you get and also ensure a smooth photograph.
If you're shooting indoors or in an area with minimal light, then shoot at a higher ISO such as ISO 1600.
1)In most cases you want to go ahead and set your ISO to an appropriate level based on your lighting and setting. Noise reduction is key.
2)Depending on the level of action in your photograph, you will want to go ahead and make sure that your shutter speed is adjusted appropriately.
3)Finally, adjust your aperture based on the amount of light you have available to brighten or darken your image.
Take a few test shots to see the lighting and quality of the photo. If your photo is too dark but you still need to shoot at a faster shutter speed (sports), consider bumping the aperture level down one f-stop. This will allow more light to enter the lens, thus producing a better lit image.
Or, if shutter speed wasn't a priority for you, you could have lowered your shutter speed by another fraction. Lowering the shutter speed allows more time for light to enter the lens and produces brighter images.
If this is something that completely blows your mind, then please do not worry because controlling every aspect of taking the photograph in this manner is usually only done in Manual shooting mode. Most cameras come with other shooting modes that allow you to adjust one of these components and the camera will automatically adjust the rest.
Aperture (Av) Mode allows you to adjust the aperture, while the camera automatically adjusts the ISO and shutter speed.
Shutter Speed (Tv) Mode allows you to adjust the shutter speed, and the camera adjusts the aperture and ISO.
Or, if you're not interested in adjusting anything on your own, then rely on your camera's Automatic Shooting Mode that will adjust everything for you to get a properly exposed photo. Just remember that shooting in this mode does not 100% guarantee the best image that you could produce in a single shot. So, don't be afraid to experiment and take photos with your own adjustments because you can't get a truly unique image until you've adjusted some of the camera's settings to get the look you are going for.