Photography is the art of capturing a moment. Light and time caught and preserved for the enjoyment of all. While I can easily describe the amount of time it took to take a photograph, (in the accompanying photo 1/800th of a second) describing the amount of light is a little more complicated.
Your lens features a system which controls the light entering your camera. Much like the pupil of a human eye shrinks and grows depending on how much light is entering the eye, the lens has aperture blades which shrink the opening of the lens so the right amount of light enters for proper exposure. When we describe how much light is used in creating an image, we describe how much light is entering the lens, known as the f-stop, through the opening of the lens, the aperture. The lower the f-stop number, the higher the amount of light entering the lens. So an f-stop of 1.8 is letting in more light then an f-stop of 5.6.
Varying apertures can have dramatic effects on your photographs. Changing the aperture of your photos will both alter the depth of focus in your photos as well as the minimum shutter speed for proper exposure. Depth of focus is how far into your photo objects appears clear. When I use an aperture of f/1.8(lots of light entering the lens) objects in the foreground and background of where I focus will appear soft or blurry. Oppositely if I use an aperture of f/32(little light is entering the lens), both the subject I focus on, as well as both the foreground and background will be in focus.
When shooting in low light environments, changing the aperture of the lens to allow as much light in as possible will result in a quicker shutter speed and a sharper image. This often allows for taking photos without a flash even when there is low light. In landscape photography, changing the aperture will allow an increased depth of field and more subjects in focus.
Lenses can have either a fixed or variable aperture. In variable aperture lenses, the maximum aperture changes depending on what focal length you’re using, or how far you’ve zoomed your lens.
To find the aperture of your lens, we’ll take a look at a Nikon 18-55mm lens. Look at the front of the lens. There is a sequence of numbers on the front of the lens telling you the focal length of your lens (18-55mm) and a ratio showing the aperture (1:3.5-5.6). This is telling you that your lens is a variable aperture lens where the lowest possible aperture of your lens is f/3.5 at the shortest focal length (18mm) and f/5.6 at the furthest focal length (55mm).
In taking both portraits and everyday photos, low aperture lenses can make your photos much more interesting at a low cost.
Confused or want to learn more? Visit Bergen County Camera to learn more about aperture, lenses, and other ways to improve your photography.