Nikon 1683 Instruction Manual - Page 20

- CONTROLS IN DETAIL-continued Setting the aperture The lens aperture determines the amount of light reaching the film plane. Generally, when you turn the aperture ring one graduation in the direction of the larger numbers, the amount is reduced by 1/2 . (This is what stopping down by one graduation means.) On the other hand, when the aperture ring is turned one graduation in the direction of smaller numbers, the amount of light is doubled. (This is known as opening the aperture by 1 stop.) The lens aperture ring clicks at the position of the numbers engraved although intermediate lens apertures are usable continuously. Lens aperture greatly affects depth of field (see page 28). With the exception of a few special lenses, Nikkor and Nikon Series E lenses enable full-aperture light measurement even when the aperture ring is moved . These lenses, which are said to have an automatic diaphragm, stop down to the set aperture only at the instant the shutter release button is depressed . 20