A sight is a device used to assist aligning or aiming weapons, surveying instruments, or other items by eye. They can also be optical devices that allow the user to see the image of an aligned aiming point in the same focus as the target. Iron sights are normally the default sight built into all firearms.
In all Battlefield games since Battlefield: Bad Company 2, the player can unlock and equip optical sights in place of the default weapon iron sights. These optical sights range from red dot sights to magnified rifle scopes and serve to give the shooter a better view while in ADS and aid in target acquisition. Additionally, some sights, such as high zoom rifle scopes, can only be attached to certain weapons.
Found on Optical and Carbine variants of various weapons, the sight is modeled after an experimental British Lee-Enfield dot sight known as Gibbs Magnifying Sights.
The optical sight provides little zoom but gives the player a dot or a T-shaped crosshair to make aiming easier.
Found on Marksman variants for single-action rifles as well as Telescopic variants of light machine guns, the sight is modeled after the Warner & Swasey Model 1913 Prismatic Musket Scope.
The sight offers medium-range magnification. The player can customize the magnification between 2.5x and 5x.
The Sniper Scope is only available on Sniper variants of single-action rifles. It is modeled after a PPCo scope.
It offers the longest range of magnification. The player can customize the magnification between 5x and 10x.
The Patrol Scope can be found on Sniper variants of self-loading rifles in the Medic class, as well as on the Patrol weapon variants introduced with the 2018 Weapon Crate update. In singleplayer, it is also used on the Scoped C96 Carbine. It resembles the Sniper Scope, but with the front and rear parts removed.
Found on Suppressive variants of light machine guns, this sight is modeled after the German Zielfernrohr 12 (ZF 12) sight, and offers medium-range zoom. The player can customize the magnification between 2.5x and 5x.
In most Battlefield games, vehicles have access to unlockable imaging/target acquisition systems. Commonly, these vehicle specializations include some sort of thermal imaging upgrade or enhanced zoom upgrade to the vehicle's main sights. In games where the player can choose their vehicle loadouts, optical upgrades are often available to many different vehicle types (in some cases however, the same upgrade can have slightly different effects depending on the vehicle it is equipped to).