When you push the shutter button halfway down it...

When you push the shutter button halfway down it...

• A. Takes a picture
• B. Changes ISO
• C. Focuses the camera
• D. Adjusts white balance

Answer: (C)

Half-pressing the shutter button activates autofocus. When you press the button partway, the camera’s AF system engages its sensors and moves the lens elements to bring the subject into sharp focus. It may also start exposure metering so the camera can determine a proper exposure, but it doesn’t change ISO or white balance at this stage. The shot itself is taken only when you press the button all the way down. ISO and white balance are adjusted separately through their own controls.

Half-pressing the shutter button activates autofocus. When you press the button partway, the camera’s AF system engages its sensors and moves the lens elements to bring the subject into sharp focus. It may also start exposure metering so the camera can determine a proper exposure, but it doesn’t change ISO or white balance at this stage. The shot itself is taken only when you press the button all the way down. ISO and white balance are adjusted separately through their own controls.