Flood Lens

Overview

In film lighting, a Flood Lens (German: Flut- oder Streulinse) refers to an interchangeable or adjustable optic that widens the beam of a light fixture, creating a broad, even flood of the scene. It is the counterpart to the Spot Lens, which concentrates and narrows the beam. The term does not refer to a specific manufacturer or fixture model, but rather a class of optics or a function within a lens system.

Flood lenses appear in two forms: as fixed interchangeable lenses that are inserted or screwed into a housing (classic with the ETC Source Four PAR), and as part of a lens set or attachment system for LED fixtures (e.g., Litepanels Nanoptic Lens Set). With Fresnel and focusable LED spotlights, the flood setting is achieved not by an interchangeable lens, but by moving the lamp and reflector relative to the lens.

Lens Gradations and Beam Angles

Flood optics are typically distinguished by standardized abbreviations that describe the beam pattern (from narrow/Spot to wide/Flood). For the common ETC Source Four PAR, the following interchangeable lenses, among others, are standard:

With the ETC Source Four PAR, only the Medium Flood (MFL) and Wide Flood (WFL) lenses produce an oval light field; the precise orientation of this oval beam can be adjusted by rotating the lens in its frame. The narrower lenses (VNSP, NSP) and the Extra Wide Flood lens (XWFL), on the other hand, deliver a round beam. The specific angles depend on the respective lens set and fixture and should be taken from the manufacturer's datasheet.

Use on Set

Flood lenses are used when a surface needs to be illuminated broadly and softly, for example, for backgrounds, fill light, or general ambient brightness. The wider the lens spreads, the larger the illuminated area and the lower the pinpoint light intensity (illuminance in lux) at the center, as the same amount of light is distributed over a larger area. Conversely, spot lenses provide a narrower, more intense beam for greater throw or targeted accents.

Since the light characteristic can be changed solely by swapping the lens, without changing the fixture itself, flood optics offer the lighting team a flexible tool to quickly adapt an existing fixture to different requirements.