Nikon 25446B D90 User's Manual - Page 198

b3: Center-Weighted Area When calculating exposure, center-weighted metering assigns the greatest weight to a circle in the center of the frame. The diameter (φ ) of this circle can be set to 6, 8, or 10 mm. This option is available in P, S, A, and M modes only. Option M φ 6 mm L φ 8 mm (default) N φ 10 mm b4: Fine Tune Optimal Exposure Use this option (available in all shooting modes) to fine-tune the exposure value selected by the camera. Exposure can be fine tuned separately for each metering method by from +1 to -1 EV in steps of 1/6 EV. D Fine-Tuning Exposure Exposure can be fine-tuned separately for each Custom Settings bank and is not affected by two-button resets. Note that as the exposure compensation (E) icon is not displayed, the only way to determine how much exposure has been altered is to view the amount in the finetuning menu. Exposure compensation (pg. 90) is preferred in most situations. L 178