Photography is full of fancy terms and complicated science, but we are here to explain it all to you in simpler terms. Today we are focusing on focal length. This term gets thrown around often, especially when looking at lenses, so you must get familiarized with it. The focal length is the distance between a camera sensor (or film) and a lens’ point of convergence. The focal length is measured in millimeters. A 50mm lens will have a score of convergence that is 50mm (or 5cm) from the sensor.
We can sit here and explain the different elements of a lens and all the science behind glass, but ultimately, what matters is how focal length affects your ability to shoot an image. The focal length is especially important when trying to pick which lens to use or buy. A lower focal length will make your subject appear smaller, while a higher one will enlarge them. Also, a lower focal length has a larger field of view, which determines how large of an area you can photograph. In simpler terms, focal length determines how “zoomed in” you are. You should pick a shorter focal length to shoot a landscape photo, and a longer one to focus on a tree in the distance.
A full-frame sensor measures 35mm, a standard which was taken from the size of the film. Anything below 35mm is considered a “crop sensor.” A smaller sensor will record a smaller image, which essentially makes a photo look more zoomed in. Understanding focal lengths and their effects on photographs will be crucial in your photography advancement. This post should be enough to get you started, but remember photography is all about getting hands-on. Go experiment with focal lengths and see what you can capture!