HD on the Rise: Cameras Part 2

HD camera lenses can be divided into two categories: lenses that have a fixed focal length and those that have a variable focal length. Fixed-focal-length lenses are called prime lenses and each prime is designed for a specific focal length. A variable focal length lens, also called zoom lens, can focus on a range of distances. There are two types of zoom lenses. A video or ENG-style zoom lens has a motorized zoom and auto iris like its video predecessor. A Cine zoom lens has no built-in motor and offers a greater rotation in the focus mechanism for more precise focus pulls.
Michael Bravin, chief technology officer of Burbank-based Band Pro Film & Digital, along with Band Pro president Amnon Band, looked for options for their HD clients. They said, “Our customers were having trouble securing high-end work because the tools weren’t available.” After some searching, they approached the Carl Zeiss lens manufacturing company in Germany, bringing to the table the collected input from the market about what a good HD lens should be. Zeiss’s response was that if Band Pro would find someone to sell them, Zeiss would build the lenses. After searching for other partners, Band Pro finally decided to go it alone. Thus began their relationship.
Other HD lens manufacturers include film lens makers Panavision and Angenieux, and video lens makers Canon and Fujinon. According to Iain Neil, chief technical officer at Panavision, “After major reconfiguration of some existing products to use for LucasFilm’s Star Wars: Episode 2, we decided to start from scratch and design custom HD lenses.” A consideration of creating lenses is the HD CCD chip, the target that incoming light hits to create and reproduce the image as an electronic signal. According to Neil, “The 2/3-inch CCD chip is only 40 percent the size of film. There is a greater sensitivity factor and HD lenses have to perform better than film lenses because of the small CCD.”
Bravin, whose line of prime lenses is called Zeiss DigiPrimes, believes, “The highest-quality lenses available in any format are prime lenses because they have a fixed focal length.” On a 2/3-inch CCD, the focal lengths are different from film lenses so Bravin offers an aid for film cinematographers. “Think of the film lens you might want to use and divide it by 2.5 to find the appropriate HD lens. For example, a 12.5mm lens in 35mm film is comparable to a 5mm HD lens.” Bravin adds, “Prime lenses are for situations where you have time to set up each shot, traditionally the feature market. ENG zoom lenses are designed more for hand focus and not situations that use a tape measure.”
From an operational point of view, cinematographer Mark Ritchie adds, “The ENG zoom depth of field is not as soft and is harder to focus. The prime lenses have a greater rotational pull, much like film lenses, so there is more control. If a subject is walking from an 8 ft distance to 15 ft, film lenses and primes may have an inch and a half movement to track with the subject. With the ENG style zoom lens, it’s more like a quarter of an inch rotation. So if someone is walking toward the lens, you’re going to have trouble.”
But when shooting an HD four-camera sitcom, changing prime lenses every scene is simply not feasible and most camera operators do their own zooming and eye focusing, so the expanded focus scales are of less of an advantage. Focus is still an issue, however. According to cinematographer Bryan Hays, “We use the Fujinon 20:1 (ENG zoom) lens and the focus is much more critical because of the higher resolution of HD. In standard definition, if the camera operators were off by a little bit, it didn’t matter. Now it does matter because it can be seen in high definition resolutions.”
The alternative to ENG zoom lenses are Cine zoom lenses, which have a greater rotational pull. But according to Bravin, “Each focal length in a zoom lens is a compromise in quality and performance.” On the other hand, Panavision carries a line of both prime and cine zoom lenses called Primo Digital. According to Neil, “Panavision’s zoom lenses usually perform as well or better than primes. Zoom lenses can cost two to three times what a single prime lens costs but they are still more economical for the supplier and the user than prime lenses.” As always, it’s a choice between quality, cost, and use.