Fishing for the
Perfect Cine Optics

Semiconductor Manufacturing Technology 07.09.2020 5 min Lesezeit

Oscar-winning movies demand high-performance cine lenses. There’s a special job for cleaning these lenses – and it’s done by the “anglers”. A peek behind the scenes reveals the special features of the lenses used to create great movies.

Kristina Hepperle doesn’t need the sea, a boat or a net when she heads to work. In actual fact, she wasn’t born to deal with the rough sea. Even though she’s an angler, she works in a darkened, shielded production area, where a sterile atmosphere holds sway. The amount of air particles, pressure, temperature and humidity are strictly controlled. At work she dons a hairnet, gloves, overshoes and coveralls. Carefully working by hand, the optical assembly engineer ensures that cine lenses are delivered to Hollywood’s big-name directors and moviemakers in pristine condition. Her aim? To achieve a flawless finish.

Josef Kohnle, Head of Operations for Camera and Cine Lenses at ZEISS
No matter whether a snowstorm is raging outside, or there’s a heatwave or a monsoon, cine lenses have to be extremely robust despite their delicate mechanics and boast exceptional reliability.

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Always in focus no matter what condition

Josef Kohnle, Head of Operations for Camera and Cine Lenses at ZEISS, is familiar with the notion of delivering premium lenses for movies and TV: “No matter whether a snowstorm is raging outside, or there’s a heatwave or a monsoon, cine lenses have to be extremely robust despite their delicate mechanics and boast exceptional reliability. Filming on a set is a very costly endeavor, so it’s easy to see why no one wants to waste any time tending to technical errors.” Such extreme conditions were experienced on the icy-cold set of The Revenant. The good news? Both main man Leo Di Caprio and the ARRI/ZEISS Master Prime lenses came out in one piece.

Cine lenses can cost as much as a mid-range car. But there’s a reason for this: they comprise premium optical lenses that have been produced to the very highest quality. Up to 120 different glass types are used to produce lenses at ZEISS. This includes challenging lens shapes such as aspheres, which can reduce optical aberrations compared to normal spherical lenses. What’s the advantage? The audience gets flawless edge-to-edge image sharpness. But it also makes the blurred background as aesthetically pleasing as possible and foregrounds the characters in the story. “Many directors see this as an essential feature!” emphasizes Kohnle.

A characteristic image that requires still consistency with every lens

For him, a highlight of the cine lenses is the ARRI/ZEISS Master Anamorphic range. It was one of the secret weapons during the filming of the James Bond movie Spectre. Cameraman Hoyte van Hoytema said: “I have the feeling that these lenses allow me to take the visions in my head and put them on film.” The lenses thus realistically capture the scenes even under extreme conditions. There is no reason to make compromises between the creative composition and the final movie.

Kohnle knows one thing for certain: “Camera crews and directors have to be able to assess the image quality in advance.” For instance, anyone who uses a set of ZEISS cine lenses expects a characteristic look from each lens in the range. And only very minimal tolerances are permitted in a single range. It is therefore crucial how carefully the lenses are adjusted during assembly so that the right focus settings are achieved for each and every scene.

Parts of a cine lens ready for assembly

Clean lenses in a transport case

Kristina fishing dust from a ARRI/ZEISS Master Anamorphic

Dexterous hands and a keen eye for detail

Behind the scenes, it’s the demands of big-name directors and dramatic movie sets that call for precision work. Ensuring cine lens cleanliness is a challenge unto itself. After all, a cine lens features between 15 and 22 lenses depending on the focal length and model line. “Every single lens is painted by hand to the edges to protect against incident light and either adheres to the metal frame or is held in place by the screw-on ring. At every step of the assembly process there is a risk of wear and tear on the black anodized metal frame,” explains Josef Kohnle. If one speck of dust should fall on the lens, it must be fished out using an angling tool – hence the term “anglers.” Kristina Hepperle’s trained eye and angling tool are certainly up to the task. That said, the “fishing out” process takes around two to five minutes per lens, depending on the size and degree of dirt.

Kohnle adds: “A lens is only deemed clean once the number and size of the particles are within the limit values for this lens. For the entire lens, this could mean that no more than five particles measuring 0.16 mm may appear in the visible zone. By way of comparison: the diameter of a human hair is roughly 0.07 mm.” So excellent vision, and spatial perception in particular, are vital in order to detect a particle on the front of the fourth lens in a complete set – that’s what it takes to be an angler at ZEISS.

Only if the lenses meet the strict quality standards can undesirable effects such as reflections be controlled and und prevented, e.g. during filming in challenging light. Once the lenses have been arranged in the barrel (housing jacket), Kristina takes the finished cine lens over for its final quality inspection – it’s not always easy to say goodbye to her masterpiece. After all, it’s a well-known fact that lenses are really put through their paces on a movie set. But “this strict work pays off, and precision delivers one thing above all else for filmmakers; the lenses thus become the perfect tool, which helps translate their idea into a masterpiece of the silver screen,” says Kristina as she places the Master Anamorphic back into the cushioned transport case, ready for dispatch.