IRNV scope

An IRNV scope, or infrared/night vision scope, is a scope with night vision, that highlights heat signatures as orange. This is useful for finding enemies at night, through foliage, or other possible cover.

Singleplayer
An M40A5 attached with the IRNV scope is equipped by the player during the mission, Night Shift, in order to compensate for the mission's dark environments.

In the last mission of the game, a Saiga 12K or MP7 attached with an IRNV can be picked up from defeated PLR insurgents at the sewer sections.

Co-Op
In co-op, the IRNV scope is equipped on many of the weapons such as the M4A1 and M249 in the mission Exfiltration.

Multiplayer
The IRNV scope may be unlocked in Multiplayer for weapons accepting optical attachments, excluding the .44 Magnum, alongside the first Service Star awarded at 100 kills; the only exceptions being the AS Val, which unlocks the attachment after 60 kills, the G53 at 90 kills, and the A-91 and the AKS-74U, which unlock it at 125 kills. Most weapons receive a simple dot reticle, but battle and sniper rifles get a mil-dot reticle similar to the x8 scope.

The IRNV scope can help counter the tactical light and glare from bright light sources, so it is easier to see the target.

Unlike other unzoomed sights, the IRNV scope sways heavily when in use and, like sniper scopes, can be stabilized by holding the sprint button ( (PC), (PS3),  (XBOX 360)) or using a bipod. The IRNV scope can be partially countered by the Spec Ops camouflage, causing only the player's vest to glow and not the rest of his clothes. Deceased players and destroyed ground vehicles quickly lose heat recognition on the sight and so targets appear fairly prominent, as little else shares the same color.

Currently in Multiplayer, enemy targets are only highlighted at fairly short range - roughly 10-15 metres, the highlight effect fading rapidly as the target's distance increases. Players using the Spec Ops black camouflage will not glow as strongly as other players.

The IRNV scope has been patched repeatedly since the game's release. At launch, the scope had a very long IR "orange glow" range and clear sight to long distances. After the first patch, the IR component was significantly nerfed, and fogging made the scope useless beyond 20 meters. The September 2012 (1.06) patch reduced the fogging effect, making the scope viable again at midrange; enemies at long range are still difficult to see. Some maps like Grand Bazaar still have fogging due to weather conditions.

Trivia

 * The scope was first seen in the Battlefield 3 Co-Op Trailer at Gamescom 2011, in which they were attached on the SVD, the M249 and the G3 during the co-op mission "Exfiltration".
 * The IRNV scope model appears to be visually based on the AN/PAS-13.
 * The scope still functions as it had prior to the patches in singleplayer and co-op.
 * Targets seen through glass like car or house windows are visible, but don't glow. This mimics glass blocking IR light in real life as well. This can be seen several times in the mission Kaffarov.
 * When looking through the scope outside of aiming, one can see that the scope model is actually transparent. This is best seen when aiming multiple times in a second.
 * The scope highlights unused vehicles and other cold objects, but not fires that are part of map design.
 * The IRNV scope can allow players to see through the visual filtering caused by being out of bounds. The player's normal vision is still compromised, and the boundary timer continues as normal.