Night Vision

Night Vision is a Fallout, Fallout 2, J.E. Sawyer's Fallout Role-Playing Game and Fallout Tactics Perk.

Fallout
With the Night Vision Perk, you can see in the dark better. Each level of this Perk will reduce the overall darkness level by 10%.

In dark indoor areas or outdoor areas at night-time, this results in an increase in monitor brightness and ranged weapon accuracy. One level of this perk increases ranged accuracy by 15%, while possessing all three levels of this perk increase ranged accuracy by 30%.

Fallout 2 and Fallout Tactics
This perk reduces darkness and darkness penalties by 20%.

You basically get a free level of this perk when you're equipped with an FN FAL with a night-vision scope.

J.E. Sawyer's Fallout Role-Playing Game
With the Night Vision Perk, you can see in the dark better. This will halve any and all penalties for darkness.

Fallout New Vegas
Night Vision appeared in Fallout: New Vegas under the name Friend of the Night and increased the brightness of the game whenever in a dark area or outdoors after 6pm (when the sun starts going down). In New Vegas the perk is not very impressive however as the Chem Cateye provides an even greater effect.

Bugs
The ranged accuracy bonus from the Night Vision perk is temporarily lost if a save game is reloaded. In outdoor areas such as towns, the accuracy modifier is re-applied after approximately a minute of game time. In indoor areas, the area must be re-entered before the accuracy is re-applied.
 * The above also applies after the Night Vision perk is selected. In otherwords, if you select this perk while indoors, re-enter the area so that the accuracy bonus for this perk is applied.