A number of factors are considered to determine the exposure: the autofocus point, areas in focus and out of focus, colors in the image, dynamic range, and back-light in the image, and so forth.
The same autofocus settings were used for all slides, enabling one autofocus point for each 3 × 3 group of fields of view.
If your subject doesn't fall under an autofocus point, select the AF point nearest to your subject, move the point over the subject, lock autofocus, and reframe.
In this shot, there was a branch closer to the camera than the subject (the white blurred area at the bottom of the shot); to prevent the autofocus locking on to this, a single autofocus area was manually selected.
Once you've done this, you can use the multi-selector on the rear to pick an autofocus point.
Two Digic III chips speed up the image processing, the handling of information from 19 autofocus points and the optional saving of uncompressed RAW and compacted JPEG files for each shot.
The autofocus points are much more visible on the Canon viewfinder, which is a matter of taste really.
It's got a magnesium, weather-sealed body, 11 autofocus points, and it saves to CF type I cards.
The A77 has a better burst rate, more autofocus points, higher ISO capability, and its LCD is more adjustable.
Hundreds of autofocus points means you get to rely on the camera's computer to have more precise focus on a subject in the frame of the camera.
