http://www.amazon.com/Camera-Photo-Film-Canon-Sony/b/ref=topnav_storetab_p?ie=UTF8&node=502394
Enhanced Durability Recognizing the often rigorous shooting conditions encountered by professional and advanced amateur photographers, Canon design engineers made the EOS 40D SLR's magnesium alloy exterior even more ruggedly dependable than its predecessors with upgraded dust- and weather-resistant construction, particularly around the camera's connection ports, battery compartment, and single-slot compact flash (CF) memory card door. Should the user inadvertently open the compact flash card door while the camera is writing to the card, a warning will pop up on the LCD screen and an open door "alarm" will sound, but the image(s) will continue writing to the memory card without interruption. The EOS 40D SLR also retains many of the outstanding features of the EOS 30D model, such as its fast 0.15-second initial start-up, its extremely durable shutter (rated up to 100,000 cycles), its top shutter speed of 1/8000 second, and 1/250 maximum X-sync flash shutter speed setting.
