Used Camera Buying Guide: Don't Buy a Used Camera Before You Read This Guide-Classic Photography or Digital?-How a Digital Camera Works-Batteries for Digital Cameras-Used Digital Camera Buying Guide -Imaging Problems and Used Digital Cameras-Buying a Used Camcorder-The DSLR Camera-Buying a Used Camera Lens-Camera Flash-Camera Aperture-Testing a Classic Used Camera-Testing Exposure Meters-Shutter Speed-Testing Shutters and Aperture Diaphragms-Note on Color Balancing-Tripods-Understanding Lighting