Lens Control, what is it?
If one aims to control a lens, one must know what lens control is, and how a lens works with a camera and other devices to achieve control. Lens control is image control. Lens control is a camera operation activity that manages the composition, focus, and light of your image. Basic control includes zooming, focusing, and iris dialing. Zooming controls a lens’s focal length, which manages the frame and perspective of your image composition. Focusing controls a lens’s internal optics to achieve a sharp, and clear resolution of your subject. Iris dialing controls the aperture blades in a lens to adjust the amount of light and depth of field in your image. Advanced control includes tilt-shifting, image stabilization, and unique lens designs. Tilt-shifting controls the barrel and optics of a lens to adjust the perspective of your composition and the critical focus plane of your image. Image stabilization electronically controls the framing of an image particularly with camera movement. Unique lens designs include macro lenses, and fish-eye lenses. For example, the unique design characteristics of the Venus Probe Lens provides control not available to most other lenses.
Lenses can be controlled by hand, automatically with the camera and lens, or with an additional device. The focus wheel on the barrel of a lens can easily be turned by hand, or turned by the press of a camera button using auto-focus technology. Image stabilization is a feature in some lenses that can be automatically activated with the flip of a switch. The iris of a lens can be opened or closed by turning a dial on the lens, or a control dial a camera. Lenses can also be controlled by an additional device. The most common device is a manual follow focus. More advanced lens control devices include F.I.Z. (Focus Iris Zoom) systems such as the Arri WCU-4. These systems include motors that engage the gears of a lens and wirelessly receive control commands from a hand unit. The Arri WCU-4 system includes 3 motors for any combination of focus, zoom, and/or iris control. The Arri SXU-1 system is a robust single motor system for focus, iris, or zoom control. Those are the wireless lens control systems in our inventory, but there are many others on the market. Years ago, Bartech Engineering introduced the Bartech Wireless Focus Control System. We reviewed that single motor Bartech system in the video below. Many of the basic principles for operating wireless control systems show in this video, apply to all of these systems, so it’s worth a look.
We provide a quick review of our 3-motor Arri WCU-4 system in our Arri Alexa Mini Documentary Package blog post below.
The process of connecting and controlling a cinema zoom lens with the Arri WCU-4 and an Arri Alexa Mini is reviewed in the video below.
The complex process of programming or “mapping” the measurements on the exterior of a lens with the Arri WCU-4 hand control unit is reviewed in the video below.
If you are interested in renting any of these devices please visit www.magrents.com, or call one of our rental coordinators at 312-465-2366!