The actor (or subject) performs in front of the reflective screen with a movie camera pointing straight at them.
The actors in ape suits were filmed on a stage at Elstree Studios and combined with footage of Africa (the effect is revealed in the leopard's glowing eyes reflecting back the light).
Front projection was chosen as the main method for shooting Christopher Reeve's flying scenes in Superman.
Effects wizard Zoran Perisic patented a new refinement to front projection that involved placing a zoom lens on both the movie camera and the projector.
The process was also used in two of the Superman sequels (but not used in the fourth movie due to budget constraints), Return to Oz, Radio Flyer, High Road to China, Deal of the Century, Megaforce, Thief of Baghdad, Greatest American Hero (TV), as well as Perisic's films as director, Sky Bandits (also known as Gunbus) and The Phoenix and the Magic Carpet.
To compensate for the large difference in the distance from the camera to the two screens an additional lens is used in the pass through image path.
The more complicated setup involves the use of two cameras, two projectors and multiple beam-splitters, light traps, filters and aperture control systems.
Introvision was first used in 1980–81 during the filming of the science-fiction movie Outland to combine star Sean Connery and other performers with models of the Io mining colony.
[9] Most movie companies brought small units to the Introvision sound stages near Poinsettia and Santa Monica Boulevard in Hollywood, California.
[citation needed] More recently, the film Oblivion made extensive use of front projection (though not retro-reflective) to display various sky backgrounds in the home set.