Use this option to fine-tune the exposure value selected by the camera; exposure can be fine-tuned separately for each metering method. Exposure can be adjusted up for brighter exposures or down for darker exposures in the range +1 to −1 EV in steps of 1/6 EV. The default is 0.
Regardless of the option selected for Custom Setting b3 [Fine-tune optimal exposure], the exposure compensation icon (E) will not be displayed. The only way to determine how much exposure has been altered is to view the amount in the fine-tuning menu for Custom Setting b3.