Ev range of the camera —continued – Nikon F3 User Manual

Page 48

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EV RANGE OF THE CAMERA —continued

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

settings.
The chart on page 35 shows the relationships between the
f/stop, shutter speed and film speed, indicating the

slowest functioning shutter speed (for metering purposes)

with any film speed/aperture combination.

Careful attention to the following instructions will assure
precise exposure, automatically, over the complete expo
sure control and meter range capability of your Nikon F3.

■ 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 f/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 down, the functioning

shutter speed becomes progressively slower until we

reach f/8 when the slowest speed of eight seconds is
functioning.

■ Auto exposure control with stop-down

metering

When using a bellows or other extension eguipment
which disengages the meter coupling device, it is neces

sary to revert to stop-down metering. Certain limitations

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 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/nupiber of f/8, the shutter speed range
would be from 1/4 second to 1/2000. 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.)

6400

1/60

3200 (4000)

1/30

1600

1/15

800

1/8

400

1/4

200(160)

1/2

100 ( 80)

50 ( 64)