Absolute durability is essential to meet the demands of professionals for continuous high-speed shooting. The D3 satisfies shutter durability tests through an impressive 300,000 cycles — twice Nikon's conventional professional cameras standard of 150,000 cycles. To achieve this, Nikon began by improving the shutter curtain, using a weave of three-layer Kevlar carbon fiber — the same fiber used in bulletproof vests — and has succeeded in developing a shutter curtain that is both light and highly durable.
But testing under ideal laboratory conditions, just for the sake of increasing publishable durability rates, is a meaningless exercise. That’s why Nikon carries out its durability tests with the shutter unit installed in the camera and throughout a wide range of different temperatures, humidities, angles and release modes, with actual professional shooting conditions in varied environments in mind. By conducting shutter release testing under conditions much harsher than a photographer would normally subject the camera to, passing the 300,000-cycles mark guarantees a comfortable durability margin for the shutter. Nikon also requires the actual cameras to clear all standards, continually monitoring data throughout testing in order to check the accuracy of exposure times and the uniformity of exposures.
In 1996, Nikon first installed its independently developed shutter monitor in the F5 camera so that accurate exposure times could be maintained. This device ensures that the shutter operates according to the set or controlled exposure time, with the result that exposures are uniform, as intended, leaving the photographer to concentrate on capturing images. In the D3, the shutter monitor has been further refined to achieve even greater compensation accuracy. The shutter monitor detects the length of time the shutter curtain is open, and if it detects a difference in time, the camera self-diagnostic system automatically adjusts the shutter speed to maintain accuracy by gradually varying the timing for the rear curtain movement. The monitor also takes into account data from the built-in temperature sensor, in a wide variety of shooting environment conditions, to ensure precise compensation. If there is a large difference between the set shutter speed and the detected exposure time, the monitor detects shutter failure and flashes an error message in the viewfinder. This frees the photographer from assuming that a shot was captured, when it may not have been up to standard.
