Nikon EL2 instruction manual EV Range of the Camera, Auto exposure control at full aperture

EV RANGE OF THE CAMERA

The camera's meter may be used only within the shutter speed range covered by the exposure value (EV) range of the meter, which varies with the aperture and ASA setting.

The chart on page 37 shows the relationships between the f-stop, shutter speed and film speed, indicating the slowest functioning shutter speed (for metering pur- poses) with any film speed/f-stop combination.

Careful attention to the following instructions will as- sure precise exposure, automatically, over the complete exposure control and meter range capability of your Nikon EL2.

• Auto exposure control at full aperture

For example, with an f/1.4 lens and ASA 100 film, the automatic shutter will function down to one second with the lens set at 1.4, and proportionately slower as the aperture is closed.

Using a standard of ASA 25 film, you may be assured of at least a four-second speed regardless of the aperture of the lens used as long as the lens is set at full aperture (refer to Table).

Using ASA 400 at f/1.4, the slowest speed is 1 /4 second; however, as the aperture is closed, the functioning shut- ter speed becomes progressively slower until we reach f/8 when the slowest speed of eight seconds is function- ing.

•Auto exposure control with stop-down metering When using a bellows or other extension equipment which disengages the meter coupling device, it is neces- sary to revert to stop-down metering. Certain limita- tions are imposed in this mode.

As lens-to-film distance is increased, the metering range (EV range) changes proportionately. For example, when an f/2.0 lens is used at 2:1 reproduction (twice life-size) the effective f/number is f/5.6 When used at f/8, the effective f/number is f/22.

When pictures are taken under minimal light levels, it is desirable to use a high-speed film (ASA 160 or higher). Using Tri-X at film speed 400 with stop-down metering, with an effective f/number of f/8, the shutter speed range would be from 1/4 second to 1/1000. Should the light level drop below EV 6, it would be out of the shutter speed range of the meter.

Table Slowest shutter speed at full aperture with any lens

ASA speed Slowest shutter speed (sec.)

32001/30

16001/15

8001/8

4001/4

200(160) 1/2

100	(	80)	1
50	(	64)	2

254

128

35