Binoculars are viewing devices used to see or spot object in long distances. In the Grand Theft Auto series, binoculars are only available as an independent "weapon" in Grand Theft Auto: Vice City Stories, and in Grand Theft Auto IV, where it is depiced as a non-interactive/cinematic prop, or as a fixed, coin-operated tower viewer.
The binocular's first-person view functionality is very similar to the viewfinder feature on cameras as well as various sniper scopes.
GTA Vice City Stories
In GTA Vice City Stories, the binoculars only used to zoom in and view far away places. They are superior to the Sniper Rifle for simple viewing, as their view is uncluttered by cross hairs. This item is first used during the mission "Leap and Bound". If the player presses the attack button while equipped with the binoculars, Victor Vance start punching the air and if that is done in front of a pedestrian, his hands will just go through the pedestrian's body and not actually do any damage. Binoculars can only be found on top of the ship in Viceport.
Interactive binocular are available in the form of Tower Optical-style tower viewers that are commonly found along scenic piers in Algonquin and the top of the Rotterdam Tower; each use of any tower viewer costs the player $1. Because they are not portable, the tower viewers are often only useful for sightseeing purposes, and have little practical use in normal gameplay.
Non-interactive binoculars are also featured in specific missions in GTA IV. In "Deconstruction for Beginners" Playboy X uses a set of binoculars to spot union members who have taken over Yusuf Amir's Castle Gardens construction site. They also appear in "Buoys Ahoy", when the first-person frame texture taken from the tower viewers is used as a stand-in for portable binoculars used by Niko Bellic and Bernie Crane to spot Dimitri Rascalov's hitmen.
First person view while using tower viewer binoculars on Rotterdam Tower, GTA IV.