Canon's zoom lenses with motorized servo drive for focus and zoom — ideal for live events and documentaries.
Technical Details
The CN7x17 KAS S (17-120mm T2.95) as the flagship of the series offers a 7x zoom with a constant T2.95 across the entire focal length range. The CN20x50 IAS H (50-1000mm) achieves a 20x magnification with a weight of 5.1 kg. All models utilize Canon's 20-pin connector for digital communication with compatible cameras and support Super35 and full-frame sensors. The integrated servo motors enable ultra-slow-motion zooms with a minimum speed of 90 minutes for the complete zoom range.
History & Development
Canon introduced the first Cine-Servo generation at NAB in 2012, based on their experience with ENG lenses from the 1980s. In 2014, the expanded series followed with the CN7x17, which offered constant aperture across the entire zoom range for the first time. The H models (Hybrid), introduced in 2018, combined manual and motorized operation in a single lens for the first time.
Practical Use in Film
Netflix series like "The Crown" use CN7x17 lenses for seamless zoom movements in dialogue scenes without visible exposure jumps. In documentaries, the slow servo speeds allow for subtle focal length changes during live shooting. The CN20x50 is used in nature films where extreme telephoto focal lengths are required with simultaneous zoom flexibility. The main advantage lies in the repeatability of camera movements for VFX work, while the disadvantage is the higher weight compared to prime lenses.
Comparison & Alternatives
Unlike Fujinon Cabrio lenses, Cine-Servos use Canon's own protocol instead of standard RS-422. Angénieux Optimo zooms offer comparable optical quality without servo drive. Modern alternatives include the Canon Sumire Primes with electronic connections or RED Pro Zooms with integrated camera communication. Cine-Servos are suitable for controlled production environments with repeatable movements, while manual zooms remain more flexible in spontaneous shooting situations.