Both cameras have impressive LCD screens, measuring 3 inches diagonally and bright enough for viewing in sunlight. But the D300's record-setting 920,000 dots are twice as sharp as the 40D's 230,000 dots, enabling us to see much finer details. Though neither camera's screen tilts or swivels (like the Olympus E-3's does), we could view them easily even at highly oblique angles. That was perfect for Live View shooting, available in both cameras, which let us compose live, sensor-generated images on the LCD screen instead of sighting through the optical finder. Each allowed us to focus in Live View by hitting the AF-On button, which momentarily swung the mirror down, engaged the optical AF sensors, then flipped it up again. This operation blacks out the screen image, briefly with the EOS 40D and a bit longer with the D300. The latter also offers point-and-shoot style contrast-detection focusing using actual image pixels. Highly precise but quite slow, it's designed specifically for tripod-mounted shooting. Curiously, the Nikon (but not the Canon) flipped its mirror down every time we shot, disabling Live View until we reengaged it manually (by half-pressing the shutter release). That's the major reason we preferred the Canon for Live View; it also has a real-time histogram, exposure simulation, optional grid overlay and two quieter shooting modes.