Canon has duplicated this feature in its new 40mm and 18-135mm STM lenses. Canon isn't the first to use microstepping motors for quiet focus, just the first to use them on a DSLR.

M3-F modules have low power consumption and maintain focusposition during power-off, and use a 3.3V input for battery-powered operation. The M3-F modules have smaller size, higherresolution, and lower ...

Canon, by contrast, always placed its autofocus motors in its lenses -- Minolta's pioneering 1985 camera, the Maxxum 7000, had its focus motor in the body. Canon was spurred into action by the ...