Nikon F3HP, 1412059 instruction manual Controls in Detail

-CONTROLS IN DETAIL-continued----------

The F3 has two separate settings for time exposures . On "B," the shutter remains open for as long as the shutter release button is depressed. On "T," the shutter stays open until the dial is rotated to another setting, making it ideal for really long time exposures. Being a mechanical setting, "T" will not cause battery drain regardless of how long the shutter remains open.

"X" provides a shutter speed setting of 1/80 sec. It is used

18to provide proper synchronization with electronic flash units other than the Nikon SB-12.

The amount of light reaching the film plane is determined by a combination of the shutter speed and the lens aperture. Since the two are interrelated, different combi- nations will give the same degree of exposure. A one-step change in shutter speed, or .a one-stop change in aper- ture setting, will either halve or double the degree of ex- posure. For example, a shutter speed of 11125 sec. lets in twice as much light as a setting of 1/250 sec., and only half as much light at 1/60 sec. For an aperture setting of fill , twice as much light as flI6 and half at much as fl8, is let in. Thus, if the correct exposure for a particular picture-taking situation is 1/125 at fill, then 1/60 at fl16 or 1/250 at fl8 will give the same exposure. The following table illustrates the interrelation between shutter speed and aperture .

The best combination will depend on the results you want. Use fast shutter speeds to freeze motion; use slow speeds to produce a deliberate blur. (See the example pictures on the opposite page.). Also, small apertures give greater depth of field, while large apertures restrict sharp focus to the main subject. (See page 26.)

A good rule to follow in preventing camera shake is to select a minimum shutter speed which is the reciprocal of the focal length of the lens in use. For example, when using a normal 50mm lens, select a speed no slower than 1/60 sec. (the closest number to 1/50). For a 500mm super-telephoto, use no less than 1/500 sec., and so forth.