Field of view in video games

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Field of view in video games

Field of view in video games (or simply field of vision, abbreviated FOV) is the extent of the observable game world that is seen on the display at any given moment.[1] It is typically measured as an angle, although whether this angle is the horizontal, vertical, or diagonal component of the field of view varies from game to game.

The FOV in a video game may change depending on the aspect ratio of the rendering resolution. In computer games and modern game consoles the FOV normally increases with a wider aspect ratio of the rendering resolution.[2]

Field of view calculations[edit]

Field of view in video games

The field of view is usually given as an angle for the horizontal or vertical component of the FOV. A larger angle indicates a larger field of view, however, depending on the FOV scaling method used by the game, it may only affect the horizontal or the vertical component of the field of view.

The horizontal and vertical FOV are calculated from the following equations:[3]

r = {w \over h} = \frac{\tan \left({H \over 2}\right) }{ \tan \left({V \over 2}\right)}

H = 2 \arctan \left( \tan \left({V \over 2}\right) \times {w \over h} \right)

V = 2 \arctan \left( \tan \left({H \over 2}\right) \times {h \over w} \right)

where r is the aspect ratio, w and h are the width and height, and H and V are the horizontal and vertical FOV.

The different values for horizontal and vertical FOV may lead to confusion because the games often just mention FOV and not whether they mean the horizontal or vertical FOV.

Field of view scaling methods[edit]

The terms Hor+, anamorphic, pixel-based, vert- and stretch are widely used in gaming discussions to describe how different video games change field of view dependent on the aspect ratio of the rendering resolution. The terms were originally coined by members of the Widescreen Gaming Forum.[4]

  • Hor+ (horizontal plus) is the most common scaling method for the majority of modern video games. In games with hor+ scaling the vertical FOV is fixed, while the horizontal FOV is expandable depending on the aspect ratio of the rendering resolution; a wider aspect ratio results in a larger FOV.[5][6] Since the majority of screens used for gaming nowadays are widescreen,[7] this scaling method is usually preferred as wider aspect ratios do not suffer from reduced FOV with it.
Field of view (FOV) in HOR+ video game in 16:9 resolution.
FOV in HOR+ video game in 16:10 resolution.
FOV in HOR+ video game in 4:3 resolution.
  • Anamorphic refers to when both the vertical and horizontal components of the FOV are fixed, typically to values comfortable on a widescreen picture, and when the resolution changes the picture is letterboxed to maintain the field of view and aspect ratio. Modern games using anamorphic scaling typically have a 16:9 aspect ratio. If this method is used by a game with a 4:3 aspect ratio, the image will be pillarboxed on widescreen resolutions.[8]
FOV in anamorphic video game in 16:9 resolution.
FOV in anamorphic video game in 16:10 resolution.
FOV in anamorphic video game in 4:3 resolution.
  • Pixel-based scaling is almost exclusively used in games with two-dimensional graphics. With pixel-based scaling, the amount of content displayed on screen is directly tied to the rendering resolution. A larger horizontal resolution directly increases the horizontal field of view, and a larger vertical resolution increases the vertical field of view.[9]
  • Vert- (vertical minus) is a scaling method used by some games that support a wide variety of resolutions. In vert- games, as the aspect ratio widens, the vertical component of the field of view is reduced to compensate. This avoids distortion of objects in the game world but results in a smaller field of view on widescreen resolutions, and may become especially problematic with extremely wide resolutions, such as those common on multiple-display setups.[citation needed][10]
  • Stretch refers to a behaviour where the FOV is not adjusted at all, and the image is simply stretched to fill the screen. This method causes significant distortion if used on an aspect ratio different from the one the FOV was originally calibrated for, and is mostly found in games made when most displays had a 4:3 aspect ratio.[11]

Field of view as an effect[edit]

Temporary changes to the field of view can sometimes be used as a special effect in video games. Reducing the field of view is commonly used to convey focus, whereas widening it may indicate lack of control. For example, in Battlefield 3 and Minecraft, the field of view narrows when the player dashes.

See also[edit]


  1. ^ Feng Zhu School of Design – Field of View in Games
  2. ^ Master Games List
  3. ^ "Projection Transform (Direct3D 9)". Microsoft. 2012-07-20. Retrieved 2012-08-12. 
  4. ^ Widescreen Gaming FAQ: Screen Change
  5. ^ Widescreen Gaming Forum
  6. ^ Example Half-Life 2
  7. ^ Steam hardware survey
  8. ^ Anamorphic
  9. ^ Pixel-Based
  10. ^ Vert-
  11. ^