The amount of exposure the film receives is determined by a combination of shutter speed and lens aperture. The larger the lens aperture, the more exposure. Likewise, the slower the shutter speed, the greater the exposure. Aperture is expressed in f/numbers with larger numbers representing smaller apertures and vice versa. For example, f/8 gives twice as much exposure as f/11. Shutter speed is expressed in seconds or fractions of a second. The numbers on the shutter speed scale are reciprocals of the actual speeds (250 represents 1/250 second, etc.).
Lens aperture and shutter speed controls are calculated so that an increase of one f/number compensates for a One-step decrease in shutter speed. For example, 1/250 at f/8 is equivalent to 1/125 at f/11. The table below shows how aperture and shutter-speed combinations are interrelated. All the combinations give the same exposure.
Setting the Shutter Speed
The Nikon F2 Photomic can be set for any shutter speed from 1/2000 second to 10 seconds either before or after the shutter is wound. Speeds from 1/2000 to 1 second are set by using the click-stopped shutter speed selector.
The numbers on the shutter speed scale stand for fractions of a second. The red line between 1/60 and 1/125 indicates the X synchronization setting of 1/80, the highest shutter speed which can be used to synchronize with a speedlight. Turn the selector until the desired speed appears opposite the white dot. You can also use intermediate settings for more precise exposure except at speeds slower than 1/80 second. At the B (bulb) setting, the shutter remains open as long as the shutter release button is held down.
For exposures of 2 to 10 seconds, set the shutter speed selector at ‘“‘B” (1). Lift up and turn the T-L finger- guard so that the slot in the ring points to “T” (2). Then turn the self-timer until the desired exposure time in seconds around the lever appears opposite the black dot (3). When the shutter release button is pressed, the shutter will remain open for the indicated number of seconds and close automatically. The shutter release button will pop out again as soon as the film-advance lever ts stroked for the next exposure.
Note that when the shutter is not released with the self-timer, the shutter release button will not return to its normal position until the T-L fingerguard is returned to its original position with the slot in the center. The self-timer cannot be cocked when the black dot is in the red region.
To make an exposure longer than 10 seconds, set the shutter speed dial at “‘B” and turn the T-L fingerguard to “T”’ as described earlier. Press the shutter release button to open the shutter. It will remain open until the ring its turned to its normal position.
The ring can also be used to prevent accidental exposure when the shutter is cocked. Pull up and turn the ring so that the slot points to ‘‘L” (lock). The shutter cannot be released in this position.
Note: When the Photomic finder is removed, use the shutter speed dial on top of the camera.
Setting the Lens Aperture
To preset the lens aperture, turn the aperture ring on the lens barrel until the desired f/number is opposite the black dot on top of the milled ring. The aperture diaphragm can be set for intermediate openings between the click-stopped settings for more precise exposure.
EXPOSURE MEASUREMENT (full-aperture method)
The exposure meter of the Nikon F2 Photomic features a center-weighted thru-the-lens metering system cross- coupled to the shutter speed and aperture controls. The meter reads the light over the entire focusing screen but favors a central area. This means that correct exposures are possible even in situations where an averaged reading would result in wrong exposure.
The meter takes advantage of automatic diaphragm feature of Nikkor Auto lenses to measure light at the maximum aperture of the lens. This insures a bright viewfinder image for viewing and focusing and minimizes the influence of light entering through the finder eyepiece. In order for the meter to measure exposure at full aperture with lenses of different maximum aperture, it must be adjusted to the maximum aperture of the lens in use. This ts done each time the lens is attached or changed by turning the aperture ring of the lens through its entire range (see p. 30, 31).
Turning On the Meter
To switch on the meter, pull out the film-advance lever Just enough to uncover the red dot on top of the camera. When the meter is not in use, press the lever flush against the camera back since the batteries are being drained continuously as long as the lever is in the ““ON”’ position.
Centering the Meter Needle
A number of different shutter speed-aperture combinations will usually result in the same exposure. The ‘‘best”’ one depends on the results desired. Use fast shutter speeds to freeze motion or slow ones to create deliberate blur. Small apertures give greater depth of field; large ones let the subject stand out against an out-of-focus background (see p. 20).
To determine correct exposure, adjust the aperture and/or shutter speed until the meter needle is centered in the U-shaped notch visible in the viewfinder (the + and — marks let you know whether you are over- or under-exposing). You can also center the needle located beneath the window on top of the finder. For fine adjustments, either the lens aperture or the shutter speed (except for speeds slower than 1/80 sec.) permits reliable intermediate settings.
Under extremely low light conditions, the meter needle may center at the “B”’ setting on the shutter speed selector. If so, correct exposure time is 2 seconds. If the needle moves erratically or cannot be centered even after all possible aperture-shutter speed combinations have been tried, then the light is too bright or dim for the meter’s range. Effective range (coupling range) varies according to the lens and film speed used. For example, with the 50mm f/1.4 lens and a film speed of ASA 100, it extends from f/1.4 at 1 second to f/8 at 1/2000 second.
For added convenience when determining exposures, the actual shutter speed and the aperture selected appear in the bottom edge of the viewfinder viewfield. This lets you adjust the exposure setting while observing the meter needle in the viewfinder.
Getting the Right Exposure
The central part of the focusing screen should always be aimed at the main subject when centering the needle. Otherwise unimportant bright or dark areas may have adverse influence on the exposure reading. If an off-center composition is desired, first measure the light striking the main subject and set the aperture and shutter speed to center the needle. Then move the camera until the desired composition appears in the viewfinder.