Through the lens, light enters the camera, strikes the sensor, and voila! A digital photograph is created. But there’s more to it than that, such as adjusting the length of time light enters the camera (shutter speed), the sensitivity of the sensor (ISO), and the size of the opening in the lens (aperture).
The aperture is simply the opening of the lens. The iris of a camera is a series of blades that adjusts the size of the lens opening, or lens aperture. By adjusting the iris after selecting an aperture setting, the photographer can control the size of the opening.
Consider the camera lens as a window. If you open the blinds fully, more light comes in; if you close them halfway, less light comes in. The aperture is the blinds, and the window is the camera lens.
While the definition of aperture is straightforward, changing it affects more than just one aspect of your photographs. Here’s everything you should know about aperture.
The Basics: What is Aperture?
Aperture is set in manual mode on a camera. The user can control the aperture, shutter speed, and ISO in full manual mode. If you’re new to aperture, aperture-priority (the A or Av on the mode dial) is a nice place to start because you can just set the aperture while the camera handles the rest.
The aperture setting is represented by an f-stop number, which is commonly written as f/2.8. Large f-numbers, such as f/22, denote a narrow aperture, whereas small f-numbers denote a large aperture.
While it’s common for newcomers to be perplexed by the fact that small numbers indicate a huge opening, keep in mind that it’s the contrary of what you’d think. Most manual-mode cameras display a graphic on the LCD screen as you modify the settings, so you may check the graphic to determine if the opening is huge or small if you can’t recall.
Each increase in f-number lets in half as much light as the previous setting, whereas each reduction in f-number lets in twice as much light as the previous setting. The same principle applies to shutter speed, so if you want to modify the aperture while keeping the exposure (amount of light in the photograph) constant, change the shutter speed by the same number of steps.
Depending on the camera model, there are numerous ways to alter the aperture. It’s usually changed with the control wheel in aperture priority mode. It’s commonly changed in manual mode on cameras with only one control wheel by holding the function button while adjusting the control wheel. Check your camera’s handbook if you’re not sure.
Keep in mind that zoom frequently impacts the aperture. When zoomed in, many cameras (and lenses) have a smaller range of aperture settings. When completely zoomed, the camera’s aperture is often not as wide as it is at a wide angle. How will you be able to tell? The camera’s (or lens’) maximum aperture will be specified in the technical specifications. When there is only one number, such as f2.8, that aperture may be attained at any focal length, which is fantastic. If two numbers appear, such as f3.8-6.8, the first represents the widest aperture at the widest view and the second represents full zoom.
How Does Aperture Affect Depth of Field?
Changing the aperture changes the amount of light in the image, but it also influences the depth of field, or how much of the image is in focus. Some photographs will have a sharp subject with a very soft background, while others will appear to have the majority of the scene in focus.
One of the most important aspects of depth of field is the aperture (the distance between the subject and the background also plays a role). A wide open aperture (low f-number) will provide a soft backdrop with only a small portion of the image in focus, whereas a narrow aperture will keep more of the image sharp.
Landscape photographers choose a narrow aperture to keep the majority of the image in focus, whilst portrait photographers prefer a tastefully blurred backdrop. The beauty of utilising manual modes, though, is being able to change aperture to achieve your own vision, whether you want a soft, sharp, or somewhere in between background.
With such a soft depth of field, it’s much easier to miss the correct focus point while utilising wide open apertures (small f-numbers). To help get the proper subject sharply focused, you might wish to use single point autofocus instead of multi-area autofocus.
How Does Aperture Affect Light?
In optimal lighting circumstances, you may easily adjust the aperture to achieve the required depth of field. However, in less-than-ideal lighting, this isn’t always the case.
When the lighting is adequate, you may balance the required aperture with the appropriate shutter speed and ISO, and select the aperture that best suits your needs. You can obtain the appropriate exposure by using a slower shutter speed if you want a narrower aperture. However, in poor light, the shutter speed is typically already sluggish, and lowering it further would result in blur. For low light, wide open apertures or small f-numbers are frequently used. (Narrower apertures can still be used if you have a tripod and are photographing a stationary picture or want motion blur.)
Low light is the most difficult to work with, but too much light can also be problematic. It’s difficult to find the right settings if you want to use a wide open aperture for a soft backdrop but also want a slow shutter speed to produce motion blur for, example, photographing a waterfall. Because neutral density filters block some light without changing the aperture or depth of field, you can shoot a long exposure in daylight with a wide aperture if you use the proper filter with your DSLR or mirrorless camera.
Finding the appropriate aperture is a delicate balancing act: you must consider both exposure and depth of field, and you may have to select one over the other at times. Understanding aperture, in either case, takes you light years ahead of simply using auto. Aperture not only regulates the quantity of light that enters a photograph, but it also gives you creative control over depth of field.