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 zero.
Custom Setting b6  fine-tunes exposure separately for each Custom Settings bank. Be aware of different fine-tuning values for Custom Setting b6 when switching banks.
Regardless of the option selected for Custom Setting b6 [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 b6.], the exposure compensation icon (
The values selected are not affected by two-button resets.