Nikon Elw instruction manual Exposure Control Lens aperture diaphragm

EXPOSURE CONTROL-Continued

Lens aperture diaphragm

The Nikomat ELW can be used with any Nikkor interchangeable lens with a Nikon F bayonet

mount. Except the reflex lens, these lenses are eq uipped with aperture diaphragms, and graduated

with a stop by stop scale from full aperture to the minimum stop number.

When a Nikkor lens is mounted on to the camera, it is designed to stay open at full aperture even when the aperture ring is turned down . The aper- ture diaphragm is set only when the shutter button is snapped and the shutter curtain is opened . This is called the automatic diaphragm mechanism. The diaphragm regulates the amount of light reaching the film, while stopping down the aperture by one graduation (from F5 .6 to F8), cuts the amount of available light in half. Diaphragm openings also have a direct bearing on the depth of field. (Refer to page 47.)

Depth-of-field preview button

The depth-of-field preview button lets you check the depth of field before shooting to make any desired adjustments. Press the button and the lens stops down to the preselected aperture to allow you to see how much background or foreground is in or out of focus.

*In full ·aperture measurement, if the shutter is released while simultaneously pressing the depth-of-field preview button, the correct exposure will not be obtained . Also, do not operate the film advance lever while pressing the button.

*When using the Auto Winder AW-l do not snap the shutter while pressing this button . If you do so by ac- cident, switch the AW-l power off and then on again to restore normal operation.

For detailed operation, refer to page 47 .

42