Occasionally the light levels might be too low for the camera to achieve an accurate focus. There are a few things that you can do to overcome this obstacle.
First, you should know that the camera utilizes contrast in the viewfinder to establish a point of focus. This is why your camera will not be able to automatically focus when you point it at a white wall or a cloudless sky. It simply can’t find any contrast in the scene to work with. Knowing this, try positioning the AF Frame over an area of contrast that is of the same distance as your subject. Then, hold that focus by holding down the shutter button halfway and recomposing your image.
Sometimes there isn’t anything to focus on. A perfect example is a fireworks display. If you point your lens to the night sky in any automatic focus (AF) mode, it will just keep searching for—and not finding—a focus point. On these occasions, enable the manual focus (MF) feature and manually focus the lens (Figure 8.4).
Don’t forget to put it back in AF mode at the end of your shoot.
AF-ass ist Beam
Another way to ensure good focus is to enable the AF-assist Beam. The built-in lamp shines some light on the scene, which assists the autofocus system in locating more detail. It won’t always flash; if the autofocus system finds enough contrast, the lamp stays off. The beam should be enabled by default, but you can check the menu just to make sure.
Enabling or Disabling the AF-ass ist Beam
- Press the Menu button.
- Use the Control dial to scroll down to the AF-assist Beam option.
- Press the Right or Left button to turn the feature On or Off.
- Press the Menu button to return to the Shooting mode.