Circular wipe where the image closes from edges to a point, created via iris diaphragm or digital radial mask.
Technical Details
Traditionally, the iris effect is created by mechanically manipulating the camera aperture during recording or by using special masks in front of the lens. Standard iris masks have diameters ranging from 35mm to 150mm depending on the film format. In digital post-production, the effect is generated using radial masks with an exponential falloff curve. The iris can be concentric (circular) or elliptical, with aspect ratios from 1:1 to 2:1 being common. Variable speeds from 12 to 96 frames per second allow for different dramatic effects.
History & Development
The iris effect was developed in 1902 by French film pioneer Georges Méliès and first used in "Le Voyage dans la Lune" (A Trip to the Moon). D.W. Griffith perfected the technique in 1915 in "The Birth of a Nation" through precisely choreographed iris movements. During the silent film era, the iris out became established as a standard transition between sequences. With the advent of sound film from 1927 onwards, the effect was used less frequently, as hard cuts were preferred. Charlie Chaplin still used the iris aperture in 1936 in "Modern Times" as a conscious nod to silent film aesthetics.
Practical Use in Film
Sergio Leone used the iris out in the "Dollars Trilogy" (1964-1966) to focus on faces in duel scenes. Warner Bros. established the effect as a trademark of the "Looney Tunes" cartoons with the characteristic black iris around Porky Pig's "That's all folks!". In "Raiders of the Lost Ark" (1981), Spielberg closes with an iris on the government warehouse to evoke the classic adventure film style. The effect is particularly suitable for time jumps, dream sequences, and nostalgic flashbacks.
Comparison & Alternatives
In contrast to a dissolve, the iris out keeps a central image element visible for longer. A fade out uniformly darkens the entire image, whereas the iris selectively focuses. Wipes operate with straight or geometric transitions instead of circular ones. Modern alternatives include zoom blur effects and radial blurs. The iris in functions as the reverse effect at the beginning of a scene. Today, iris out is mainly used for stylistic homages or deliberately nostalgic effects.