Photography Cheat Sheet: Understanding Focal Lengths

If you’re new to interchangeable lens cameras, this cheat sheet should help you understand how focal length affects your photos.

The primary advantage of interchangeable lens cameras, as the term suggests, is that you’ll be able to shoot using different lenses with varying focal lengths. Therefore, learning how focal length works and its relationship with the angle of view will help you choose the right lens for the kind of photography you want to do. For this, we’re sharing a cheat sheet that will serve as your handy dandy guide.

To help us understand the difference between different focal lengths, Digital Camera World came up with a simple but effective cheat sheet that shows what a scene looks like when shot in different focal lengths. It demonstrates how the focal length of a lens affects the angle of view that you can see through the viewfinder, and ultimately, how much or how little of the scene you can capture in your shot, depending on the effective focal length (EFL).

Now, let’s dissect the cheat sheet. In the tutorial included in this cheat sheet, we learn that the smaller the number, the wider the focal length is. This produces a wider angle of view that allows you to fit more of the scene into the frame. Take note of the example above for 11mm as compared to 55mm. The former would be a good choice for landscape photography, while the 55mm is often the choice for portrait photography. If your lens has only one figure in its title (50mm, for example), it only provides one focal length. But if it has two figures (like 18-55mm), it will allow you to use the two focal lengths that are numbered and everything else in between.

However, the cheat sheet also mentioned the effective focal length (EFL). This is determined by your camera and lens combination. Cameras with sensors smaller than a Full Frame sensor (also referred to as crop sensor) will reduce the angle of view and increase the effective focal length. So, an 18-55mm lens paired with a camera with an APS-C sensor yields an EFL of around 27-82mm.

Ready to take a deeper dive into the topic? We have lots of resources for you, but for starters, you might want to read about the five focal lengths we think every photographer should try.