Thursday, February 24, 2011

Focusing on Focus

There are several components needed to create a great photograph including subject matter, composition, exposure, presentation, and focus.

Pardon the pun, but today, I'm going to focus on the focus. In doing so, I'll also have to incorporate some rules of composition, and touch on depth of field and selective focus. It's hard to talk about these issues without getting into shutter speeds, lens focal lengths, and special effects (both by camera settings, and through the use of filters), but we'll save that for another day.

In the days of film cameras with manual focus, things were a bit easier to deal with. You turned the lens focusing ring until the image was sharp, and you took the picture. With the advent of auto focus, things changed a bit. Most cameras had a small box in the middle of the viewfinder, and whatever was in the box, is what the lens focused on. This worked out fine if you had one subject, and you put it in the middle of the picture. Unfortunately, many pictures contain more than one person, and none of them were dead center in the picture. Then along came the focus lock setting on cameras. Now you can aim at one person, press the focus lock button, then re center your photo while the focus is locked. Even more amazing was what Canon called "eye control". This was a sensor located just below the eyepiece on the back of the camera, that would watch your pupil to see where it looked in the viewfinder, and would then focus on that part of
the picture.

Technology advanced further, and along came multiple focus spots (or zones). This meant that your camera would automatically set the focus based on more than one point in your viewfinder. Some cameras even allowed you to select the points in the viewfinder that you wanted to focus on. One of the latest innovations is called "face detection". This allows the camera to locate a face, or multiple faces in the photo, and then focus on them. This technology has advanced to become known as "facial recognition", and for most of you on social websites, "facial tagging".

With all that being said, here are a few basic guidelines to keep in mind:
  • If you're photographing a large group of people (3 or more rows), focus about 1/3 of the way in from the front of the group.
  • Use a smaller aperture when possible to get greater depth of field, and thus get more in focus.
  • Set your focus point on something with contrast (most auto-focus sensors won't lock in on a solid color).
  • Make sure that there is enough light for the camera to see so that it can focus properly. Some cameras and flash units have an infrared sensor to assist you.
  • Use a tripod when possible, as you will get sharper photos.
  • Consider turning on the IS or VR function on your lens. (This is best when not using a tripod, and shooting on slower speeds. Read more about IS and VR here.)
  • Don't forget that for a moving subject you'll need a faster shutter speed.

- Arthur Z.