The Sony HDR-CX115 features a 25x optical zoom. Optical zoom lets you press a button on your camcorder and enlarge your subject. Zooming in lets you get closer to your subject without having to move closer to them. A handy feature you'll find in all camcorders. Optical zoom uses the camcorder's lens to enlarge the view, and won't distort the image the same way that digital zoom does. A camcorder with a 10x digital zoom will bring the subject ten times closer than it appears to the naked eye.
More information on Optical Zoom
Photoxels.com - Optical vs. Digital Zoom
