The Variable Zoom can be found on all sniper rifles, the Crossbow, and the G11, with three levels of zoom. Levels of zoom can be chosen by pressing the melee button while scoped in. Also, the level of zoom does not change after zooming out of the scope or switching weapons, only if the player drops the weapon.
The Variable Zoom is available for the G11 and Sniper Rifles, but not the Crossbow, unlike in campaign. Other than that, the scope behaves the same. The low zoom can help the player engage closer targets, while the highest zoom level is more than the default sniper scope, which can help the player engage targets at farther ranges. The Variable Zoom scope does not bounce as much on the initial zoom in as the regular scope, as it is zoomed in less. For this reason it is favored more for "Quick Scoping".
It's also slightly bugged in split-screen play. The second level of zoom goes much farther than it should, which makes the third level zoom a foot further or so.
The Variable Zoom returns in Call of Duty: Modern Warfare 3. It was first seen in the Multiplayer World Reveal on a Dragunov as a player's secondary weapon. It was then seen equipped on the AS50 at COD XP, it is known as the "Variable Zoom Scope". The scope has three different zoom levels, a 2.4x zoom, a 4.8x zoom and a 9.6x zoom. It is unlocked exclusively for Sniper Rifles at Weapon Proficiency Level 22.
In the campaign, a variable zoom scope that operates exactly like the variable zoom scopes in Modern Warfare and Modern Warfare 2 appears in the mission Blood Brothers.
The Variable Zoom returns in Call of Duty: Black Ops II. It is an attachment for the sniper rifles, light machine guns, and the Crossbow. It now has only two levels of magnification unlike the previous ones. The attachment can be combined with the Dual Band Scope to create a hybrid optic. The attachment decreases centerspeed by 10% for LMGs; therefore it is best suited for low recoil LMGs such as the Mk 48, but a poor choice for the QBB LSW which has high recoil and poor long range damage.
"While scoped in, press RS/R3 to adjust between 3 different zoom levels."
— In-game description.
The Variable Zoom, now called Variable Zoom Lens, appears in Call of Duty: Ghosts. Similarly to Modern Warfare 3, the Variable Zoom in Ghosts has three zoom levels, and is only available to sniper rifles.
The Variable Zoom returns in Call of Duty: Advanced Warfare with the name Variable Zoom Scope. It is unlocked by getting 20 Kills with the Lynx, MORS, NA-45 or SVO. It is integrated to the Lynx "Variable" supply drop variant. On the Atlas 20mm it is only available in Exo Survival. The variable zoom has a disadvantage in that the minimap is no longer visible when scoped it.