Understanding Aperture in Photography
Aperture in photography is one of three elements that affect exposure; the other two being shutter speed, and ISO. The three elements are known as the Exposure Triangle.
Aperture controls:
- Exposure: How bright or dark the image is.
- Depth of Field: How much of the photo is in focus
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What is Aperture
Aperture is the opening in a lens which light passes through to the camera’s sensor. It is measured in f-stops, written in numbers such as 1.4, 2, 2.8, 4, 5.6, 8, 11 and 16, which determine the amount of light let through.
In photography, aperture works like the pupils in our eyes. It widens and narrows, allowing more or less light to pass through to the camera’s sensor.
Larger apertures allow more light in and result in brighter images. Smaller apertures let less light in and result in darker images.
Aperture and F/stops
The f-stop is the setting that controls the size of the aperture and how much light passes through the camera lens.
Aperture numbers appear to be contradictory, and can be a bit confusing when you are first starting out. The numbers seem to be completely the reverse of what you expect.
The easiest way to remember which f-stop to use is:
- A smaller number = larger aperture, lets more light in, has a shallow depth of field
- A larger number = smaller aperture, lets in less light, has deep depth of field
Each step down lets in half as much light: So, when you go from f/2.8 to f/4, you are cutting the aperture in half. When you go from f/4 to f/5.6, you cut the aperture in half again.
If you need to double the aperture size, you just go in the reverse direction: from f/5.6 to f/4, etc.
Aperture and Depth of Field
Using aperture to control depth of field is an important creative tool in photography. It can add dimension to your images, and make them more interesting.
Depth of field is determined by the aperture (f-stop number) that you use. It affects the amount of your image that is in focus from the foreground to the background.
A smaller f-stop number produces less depth of field, and a blurrier background. A larger f-stop number produces a large depth of field, resulting in sharper foreground and background.
An image with a “large” or “deep” depth of field (larger f-stop number) will have a look like this:
See how the sharpness extends from the foreground to the background? A smaller aperture (higher f-stop) will give you a larger depth of field, and allows you to keep a greater amount of the image in focus. It’s normally used in landscape photography or for group shots.
On the other hand, an image with a “thin” or “shallow” depth of field (smaller f/stop number) will have a look like this:
So, an image with a shallow depth of field, blurs the background and helps the in-focus subject of the photo stand out. This is useful for portrait & food photography, and is a creative photography effect is known as bokeh.
Conclusion: Aperture in photography
Hopefully, you now have a better understanding of how aperture works in photography. The best way to figure it out it to start shooting. Try different apertures and see what they do! It really is the best way to get the hang of it!
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