Be in command of the camera aperture to achieve better shots
The camera aperture determines how much light will go into your lens. Together with the shutter speed, it works to control light, which is a central element in photography. Experienced photographers know that opening the camera’s aperture in close-ups allows for more light to enter the lens, which makes the background more blurry and the object more pronounced.
What is the camera aperture?
A camera aperture is a mechanism that sets the diameter of the “hole inside the lens” through which light passes. Opening the aperture enlarges the hole, and closing the aperture makes it smaller. Imagine partly covering your eye with your palm rolled into the shape of a tube. The camera aperture works like the opening and closing of your palm.
The values representing the camera aperture are called f-stops and are universal across cameras and lenses (the aperture set at f/2 will let the same amount of light into a Canon camera as it will into an Olympus camera).
A short explanation on f-stops and on how they change the amount of light
As we mentioned, the amount of light that gets into the lens by the opening of the camera aperture is represented by f-stops. The common f-stops are:
f/1.4 f/2.0 f/2.8 f/4 f/5.6 f/8 f/11 f/16 f/22
There are two key things to know about f-stops:
- The higher the value, the smaller the aperture and the less light that gets in.
- Every single-step reduction in the f-stop value reduces the amount of light by a factor of two.
In specific terms, the camera aperture is the ratio between the diameter of the lens and the focal length (if this sentence brought you back to your high school math days, relax - you can ignore it and focus on the two simple rules above).
You can read up on composition – what is it and how do you understand and exploit natural composition.
A long and detailed explanation on camera aperture and how different f-stops influence light
The ‘f’ in f-stop stands for the diameter of the lens and the number following it is the value by which to pide it. An example: when you set the aperture to f/2 with a 50-millimeter lens, you will get an opening of 25 millimeter (50 pided by 2). Similarly, using the same lens set at f/4 will mean that the aperture will be 12.5 millimeters.
Since f-stop values are fractures, the larger the f-stop the smaller the aperture. Setting the aperture at f/2.8 will let less light than setting it at f/2.
This is important: if you take a square and pide each of its sides by two you’ll end up with four smaller squares. You get four times the squares that you started with (this applies to all shapes). It’s the same with the camera aperture – if you half the diameter of the aperture the reduction in light will be more than by a factor of two. So setting the aperture at f/2 lets in four times more light than setting it at f/4.
- Read more about f-stops to see illustrations for different values.
- Continue reading and learn how different aperture sizes have different photographic results.
How to set the camera aperture?
Choose one of the following two options:
- Set the camera to ‘A’ or ‘AV’ – denoting Aperture Priority. In this preset you determine the camera aperture and the camera automatically sets the proper shutter speed.
- Set the camera to ‘M’ – denoting Manual. In this preset you have more control, but there’s more room for error (can lead to under- or over-exposing your shots).
Before you continue reading, open one of the following instructional articles in a new browser window: leading lines,composition, focus, camera lenses.
How to use the camera aperture to influence sharpness
When you open your eyes first thing in the morning you are flooded with light and that makes seeing difficult. It is the same for the camera – when flooded with light things become blurry. When you open the camera aperture and let a lot of light in, it makes it hard on the camera to capture near and far objects. Similarly, when you close the aperture and reduce the amount of light, it can better focus on near and far objects. An example: open the aperture and you will be able to take a photograph in which your kid comes out clear and the lush valley behind him is hazy. This will make your kid stand out in the photo.
When you want to show the nearby trees, the lake, and the mountain in the background. Use a small aperture, so that less light enters the lens, and all objects come out sharp.
To sum up: a large camera aperture makes the object that you are focusing on come out sharp and leaves other objects blurry.
The difference between opening the aperture and using a slower shutter speed
Besides changing the camera aperture, there is another way to influence the amount of light that gets in the camera – changing the duration in which the aperture is open and can receive light. Even when set to the largest aperture, little light will get through if the duration of the shutter opening will be very short.
Change the camera aperture when you want to impact the sharpness of objects in the photo. On the other hand, change the shutter speed when you want to impact how motion photography is handled (for example, creating a smoothing effect of flowing water, freezing a horse in mid air). Together, the camera aperture and shutter speed determine the amount of light that gets into the lens, and the camera usually ‘knows’ how to balance things out when you set the aperture too small (it will slow the shutter down, which might result in blur caused by the movement of your hand).
It’s important to notice that the blur caused by a slow shutter speed is different from the blur caused by a large aperture. The former will likely cause blur for objects that are in motion (or the entire photo if your hand wasn’t steady), and the latter will blur objects that you didn’t focus on. The results are entirely different (the exception to the rule is that you could change the shutter speed to cause blur in objects that are not in focus).