The D3 is Nikon's first camera to employ a stepping motor built into the camera body for aperture control. This large microprocessor-controlled stepping motor is used simultaneously for driving the aperture and for position control. With smooth movement through 18-degree steps per pulse signal and a freely reversible drive, the motor achieves high-precision performance. What's more, less debris is generated compared with the ratchet mechanism used for the conventional position control method. And it enables exposure preview during Live View shooting as well as real-time aperture changes. This powerful, high-precision stepping motor also makes a huge contribution to continuous 9 fps high-speed photography with the D3 because it allows aperture settings right down to the minimum aperture, irrespective of the lens being used and without a reduction in shooting speed.