Rotation range of the focus ring from minimum focus distance to infinity — on cine lenses typically 270° for precise control.
Technical Details
Professional cinema lenses like Zeiss Master Primes have a standardized focus throw of 300°, while Cooke S4/i lenses operate with 270°. The focus ring features a pitch of 0.8 mm and is marked with precise distance indicators. Follow focus systems translate this rotation via gears at a 1:1 ratio or with reduction ratios up to 1:4. High-end lenses use cam-driven focusing with a non-linear characteristic – the close focus range occupies proportionally more rotational travel than the far focus range.
History & Development
In 1920, the French company Kinoptik first introduced cinema lenses with an extended focus throw to enable precise manual focus pulls. In 1935, Mitchell Camera Corporation standardized the 270° focus throw for Hollywood productions. In 1972, Panavision expanded the standard to 300° for their Primo series. Modern cinema lenses since the 2000s additionally integrate encoder technology for digital focus acquisition for remote systems and virtual production.
Practical Use in Film
Emmanuel Lubezki utilized the extended focus throw of Leica Summilux-C lenses in "Birdman" (2014) for fluid focus pulls in the continuous long takes. Roger Deakins relied on precisely programmed focus pulls across the entire 300° range of Signature Primes for "1917" (2019). The longer focus throw allows for smoother transitions and millimeter-accurate focus positioning. Documentary filmmakers often prefer shorter focus throws for spontaneous reactions, while narrative film productions value the precision of long focus throws.
Comparison & Alternatives
Still photography lenses, with their short focus throw of 90°, require extremely fine manual dexterity, making them unsuitable for professional film productions. Servo focus systems like Preston HU3 bridge this limitation through electronic speed control. Modern alternatives include wireless focus systems (Teradek RT) and AI-assisted autofocus technology in cameras like the Sony FX9. Cine modifications of still photography lenses artificially extend the focus throw to 180°-200°, but do not achieve the precision of native cinema lenses.