The focal length that you use when shooting an image has a big impact on the photo you create! And that impact goes far beyond the simple matter of how much you can fit into the frame of your photo.
I know I sometimes get stuck on this. I’ll be shooting a scene and I want to include more or less of that scene in my image.
So, assuming I don’t want to move my camera, I’ll change the focal length I’m shooting with. Remember that this is a measure of magnification and that means that it determines the field of view. If I am shooting with a zoom lens–one that allows me to vary the focal length–I’ll twist the barrel to change that zoom. If I’m shooting with a prime lens–a single focal length lens–I’ll switch out the entire lens.
In either case, increasing the focal length reduces the field of view, limiting the amount of the scene that shows in your image. Decreasing it does the opposite. It enlarges the field of view and allows more of the scene to be included in the frame of your photo.
But changing the focal length impacts your photo in ways far beyond field of view. And if you want to learn to control and improve your images, this is an important thing to understand…because it helps you decide which focal length to use for any particular image to get the look that you want.
The focal length impacts your photo in three ways:
- It affects the field of view, or how much of the scene in included in the frame of the photo.
- Focal length changes the perspective of an image, or how the different objects in the frame appear relative to each other.
- It affects depth of field, or how much of the scene is in focus.
If all of this sounds a bit confusing, no worries. Mike Browne of Picture This (Imaging) Ltd. has created a series of videos that do a wonderful job of explaining the impact of focal length on your images. They are definitely worth watching!