Nikon N90 instruction manual Exposure Compensation, About reflectance

EXPOSURE COMPENSATION

Exposure compensation is a photographic technique that enables you to vary the final exposure settings from those measured by the camera'slight meter. Nikon 's3D Matrix Metering employs methods of exposure calculation that automatically apply exposure compensation, depending upon scene brightness and contrast. As a result, your subject, whether it is centered in the viewfinder or not, is given corrected exposure in most lighting situations.

We do not recommend using any manually or automatically applied exposure compensation when using Matrix Metering. If you identify an extreme condition under which Matrix may have some difficulty, such as a severely backlit scene or one with extremes of contrast, we recommend using your camera's other built-in meters, Center-Weighted or Spot. Ultimately, only you know what the subject or a part of it requires in terms of exposure measurement. That'swhy the N90 camera incorporates three meters plus a variety of exposure compensation systems. The photographer'screativity is always the final deciding and controlling factor. To use the various exposure compensation functions, please refer to the following.

•Using AE-L (Auto Exposure Lock) lever (pp. 88-89)

•To obtain meter reading for a particular subject in Manual exposure mode (pp. 90-91)

•Using exposure compensation button (pp. 92-93)

•All Mode Exposure Bracketing (MF-26 users only) (see MF-26 instruction manual)

Results will vary, depending on conditions, so you will want to experiment with each method .

About reflectance

When using the Center-Weighted or Spot Meter, always keep in mind that the exposure indicated will assume that the subject'srefiectance is equivalent to 18%. If the subject varies from this reflectance, you must make an adjustment to exposure. Generally speaking, a white subject will have about a 90% reflectance, and an adjustment of 2.5 f/stops (further open) will bring the exposure back to the equivalent of an 18% reading. As another rule of thumb, when shooting a landscape, the light meter reading from green grass is roughly equivalent to 18% reflectance.

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