The focal length of the lens is one of the first things I think about when creating a photo. The lens I choose has a huge effect on the composition and the emotion I want to capture so it’s important to understand what different focal lengths do for an image.
The focal length affects how much of your scene is in the frame, how close objects in the frame appear, and the size of the subject.
Field of View
A lens with a shorter focal length like 30mm will have a wider field of view than a lens with a longer focal length like 70mm. A lens that has a wider field of view can capture more of the environment.
The photo on the right has a lot more of the environment in the frame than the photo on the left. If context and surroundings are important to tell the story, then use a wider angle lens, i.e. one with a shorter focal length.
Distance between objects
Have a look at this animated GIF showing 4 images captured with different macro lenses while keeping Him-Dude™ relatively the same size in the frame:
Notice the door in the background appears much further away and smaller in the 30mm shot vs the 70mm, but the distance between it and Him-Dude is physically the same. I didn’t move the minifig at all, just the camera.
The focal length changed the composition as a result: my hero is framed within the door in the photo on the right but not so much on the left.
Emotionally, the two feel different as well. The shot on the left feels more immersive while the shot on the right feels more isolated.
Picking the Right Focal Length
Lenses are creative tools that help you tell stories but they also solve technical problems.
There are more things to think about than the result of the photo: you might be limited physically with how close you can get, whether you have a tripod or not, how your camera body deals with low light and stabilization, and so on.
These are just some of the questions I ask myself when deciding on a lens. You can find those in my toy photography workflow.