The Ultimate Guide to Understanding Aperture

In photography, an aperture is the opening of a lens used to control the amount of light necessary to expose the sensor/film; in addition, the aperture is used creatively to control the compositional use of depth of field. A smaller (closed) aperture restricts light and increases the depth of field in a scene, whereas a larger (open) aperture allows for more light and decreases the depth of field within a scene.

But, why does this matter to you? By understanding aperture, I can help you capture images that better achieve your creative vision. This article is designed to be the ultimate guide to understanding aperture and comes from our full-length course Photography 101. However, I want to be clear, this article, along with the education on SLR Lounge, are not designed to be technical manuals, but rather field guides.

We create real-world field guides designed to get you out and shooting as quickly as possible. For those who are interested, we will include additional technical details and facts at the end of the article. Let’s dive into the first piece of this article, which is using the aperture to control your image exposure.

Aperture for Exposure Control

Aperture is one of the three pillars within the exposure triangle, shown below.