What does an optical zoom do?

• A. It digitally crops the image to enlarge the subject
• B. It increases the camera's ISO to magnify the subject
• C. It uses the physical principles of optics to make your subject appear closer to the camera
• D. It extends the shutter speed to achieve zoom

Answer: (C)

Optical zoom works by changing the focal length of the lens itself. When you zoom, internal lens elements move so the focal length lengthens, which makes the image of the subject larger on the sensor while preserving detail and sharpness. This is different from digital zoom, which just crops or enlarges the image after it’s been captured and tends to lose image quality. ISO and shutter speed affect brightness and exposure, not how close the subject appears. So the way you actually magnify the scene, without sacrificing quality, is by using the lens’ optics to bring the subject closer.