Field of view

Field of view (FOV) is "the extent of the observable game world that is seen on the display at any given moment", "usually given as an angle for the horizontal or vertical component" (Wikipedia: Field of view in video games).

Focal length, distortion and which axis each engine uses are on cameras, lenses and field of view. This page covers screen-shape scaling, typical values, comfort and the conversion maths.

#Horizontal, vertical and screen shape

The same view has two angles. Which one a game holds fixed decides what happens on wider screens. Wikipedia lists the common schemes (Wikipedia: Field of view in video games):

• Hor+: "the vertical FOV is fixed, while the horizontal FOV is expandable." Wider screens see more at the sides. Wikipedia's article cites Half-Life 2 as an example (Wikipedia: Field of view in video games).
• Vert−: "as the aspect ratio widens, the vertical component of the field of view is reduced to compensate." Wider screens lose view at the top and bottom.
• Static (formerly anamorphic): "both the vertical and horizontal components of the FOV are fixed", so the image is letterboxed or pillarboxed.
• Pixel-based and stretch scaling also exist, tying the view to resolution or simply stretching the image.

#Converting between horizontal and vertical FOV

On a flat screen, the two angles are linked by the aspect ratio (width ÷ height):

horizontal = 2 × atan( tan(vertical ÷ 2) × aspect ) vertical = 2 × atan( tan(horizontal ÷ 2) ÷ aspect )

#Typical values: console versus PC

Wikipedia states that "a narrow FOV of around 60 degrees is used for console games", while "a larger FOV of 90 to 100 degrees is usually set for PC games" (Wikipedia: Field of view in video games). The reason is viewing distance: a TV across the room "subtends a small part of the viewer's visual field", while a monitor "occupies a larger amount of the viewer's vision" (Wikipedia: Field of view in video games). Wikipedia does not state whether these figures are horizontal or vertical.

When a narrow console FOV is played close to a monitor, the result is "an uncomfortable sensation likened to viewing the scene through binoculars" that "may lead to disorientation, dizziness, or nausea" (Wikipedia: Field of view in video games).

#FOV sliders in shipped games

Microsoft's guideline lists examples (Xbox Developer Docs: Xbox Accessibility Guideline 117: Visual…):

• Halo Infinite: an FOV slider whose description explains the "fishbowl" effect at higher angles.
• Minecraft: "FOV angle up to 110 degrees."
• Assassin's Creed Valhalla: a "Close Camera setting for third-person view", the third-person equivalent.

#What it means for environment art

• Dress for the range. At a wide setting, players see corners and edges you may never have checked; at a narrow one, a side exit can fall off screen.
• Finish the sides of vistas. Under Hor+, ultra-wide players see far more at the edges. See sightlines and vistas.
• Check performance at the widest setting. A wider view can bring more objects on screen. See draw calls and level of detail.

#Related pages

cameras, lenses and field of view · scale and proportion · sightlines and vistas · grids and metrics · colour blindness and accessibility · level of detail · performance and profiling

#Further reading and watching