Circular fisheye photograph showing extreme wide-angle distortion
Circular fisheye photograph of the Oude Kerk, Amsterdam — showing the characteristic 180° field of view · Photo: Danielteolijr · Source · CC BY-SA 4.0

What is it?

A fisheye lens is an ultra-wide-angle lens that produces a strongly curved, barrel-distorted image covering 180° or more. In the fulldome world, fisheye lenses serve two critical roles: projecting domemaster imagery onto the dome, and capturing hemispherical content for dome production.

Types of Fisheye

TypeProjectionUse
Equidistantr = f × θStandard domemaster format
Equisolid angler = 2f × sin(θ/2)Some capture lenses
Stereographicr = 2f × tan(θ/2)Artistic/architecture

The equidistant projection is the standard for fulldome — it maps angular distance linearly to radial distance in the image, matching how domemaster frames are structured.

In Projection

Single-projector fulldome systems use a fisheye lens mounted on a projector aimed at the dome centre. This is the simplest fulldome setup but limited in resolution and brightness. Dual-fisheye systems use two projectors with overlapping coverage for better pixel utilisation.

In Capture

Fisheye lenses on cameras capture hemispherical or full-sphere imagery for dome content. Notable tools include the Canon RF 5.2mm dual fisheye (stereoscopic 180°), Entaniya 220° lenses, and multi-camera rigs stitched in software.

See also: Domemaster → · Projection Blending → · Fulldome →

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