To focus or not to focus
With the array of cameras out there, from DSLR's, to camcorders; there is more than an abundance of great options to choose from when you want to create your own film. Whichever device you use, one of the most important things when filming, and this goes for any film of any style and genre, is the ability to focus. It's such a simple thing to say, but a badly-focused film is one of the most off-putting things for an audience. That said, some unfocused scenes add mystery and suspense. Often in films you'll see an unfocused subject, that slowly becomes focused. This can be used to heighten the senses and build-up to a dramatic reveal.
Focusing is simple, you adjust your lens to the point where you can see the subject in its clearest detail. Even with auto-focus, which is usually the standard on cameras today, it’s always good to learn some techniques that will help you be in complete control of focusing. As Tommy Penner writes, "Most cameras today have autofocus built in, and you might be wondering why we don’t just leave it on all the time. Autofocus can be pretty good at guessing what subject you want in focus, but it may not always get it right. Lots of movement within the frame or moving the camera itself can cause a distracting “pulsing” effect as the autofocus decides what subject should be in focus. Manual focus is the setting we need to assure all our shots are tack sharp on the subjects we want."
As one of the essential techniques in cinematography, focusing offers the viewer a wide range of emotional and psychological content. In No Film School, V Renee writes on the subject of focus, “We're talking shallow depth of field here -- the same effect that happens when your eyes focus on something close to you. Naturally, when we see this on-screen, our brains interpret it as depth. (However, deep depth of field doesn't, by contrast, suggest lack of depth. Gregg Toland, for example, expertly plays with deep focus in the iconic shot in Citizen Kane.)”
Now, there’s a number of lenses to think about when filming, and some will already do the job of focusing. The telephoto lens is built to focus intensely, shifting all the audience's attention to that one subject, and making everything in the background and surrounding area superfluous. The telephoto lens is primarily used to bring far away subjects into close proximity, offering a flattering closeup.
Over at Learn About Film, Tom Barrance has written an in-depth article on using different lenses when filming, which covers the broad spectrum of focusing on different aspects. For example, “Some filmmakers use pull focus or rack focus to change focus during a shot. This can change the emphasis from one part of the scene to another. To do this effectively you need a system still camera or a large sensor video camera with a lens that is easy to focus manually. You can buy follow focus attachments that make this easier. It’s not worth trying to do this if you have a small automatic camera.”
From the simple method of bringing a scene to life, to the more intricate ways of bringing a subject to the fore, there are numerous points to consider when learning how to focus, but like most things in cinematography, it’s all about timing.