What is focus?
Focus in photography and cinematography is the process of optimizing sharpness through adjustments made to the camera lens.
Lenses consist of various elements that allow light rays to pass through and converges them onto the film or digital sensor. Aperture also has an impact on focus, as bigger openings result in a much smaller depth of field.
The areas or focal planes of your image that are in focus are highlighted to the viewer and determine how much detail they can make out. They’re usually referred to as the plane of focus.
AF vs manual focus
Manual focus is usually done by turning a ring on the lens physically. Its success depends on the photographer’s skill level. It’s a way to make precise adjustments, especially in lighting conditions that autofocus would struggle with.
It’s mainly used for still photography, often for landscapes. If this is your next project, understanding hyperfocal distance could make a great difference.
Autofocus or AF is a process where the camera system moves elements in your lens to change focus with a motor. It’s easier and faster to use than manual focus. Today’s technology allows it to track movement and predict motion in real-time. It’s the perfect choice for beginners or when shooting fast-moving subjects, like in sports and wildlife photography.
For a comprehensive explanation of various autofocus options you need to understand, check out this article on focus on photographylife.com.
Where to focus
When deciding where to focus, most of the time your subject is the obvious choice. Depending on the size of whatever you're shooting, and the distance of the camera, you might have to pick which specific part is the most important. When taking portraits, this is probably the subject’s eyes. If you’re doing a tracking shot of a car, it could be the wheels, the front, or even the headlights.
You may also decide to take a more artistic or adventurous direction. Use focus to direct attention to any specific part of your images. The limit is only your imagination!