Speaking at Camerimage, a film festival devoted to the art of cinematography, Patrick Lin, the director of photography on Pixar Animation Studios’ “Inside Out,” explained how his team used virtual cameras and lighting in a similar way to how a cinematographer on a live-action movie would do.

Lin, whose full title on the movie is d.p. — camera and staging, was joined at the panel discussion this week by his fellow crew members Kim White, d.p. — lighting, and Adam Habib, camera and staging lead.

In Lin’s overview of the production process, he explained that whereas in live-action the phrase is “Lights, camera, action,” in computer animation it is “all mixed up.” “It is actually ‘Camera, action, light’ — in other words, it is layout, animation, and then lighting,” he said.

Where animation and live-action differ is that the shooting, or layout, and lighting of a scene are done separately, but naturally they have to work hand in hand.

“Cinematography at Pixar is a collaborative effort between two departments — layout and lighting,” Lin said. “And layout is responsible for the camera and staging part, and it is a first step to defining what the film is going to look like cinematically. And lighting is responsible for light, shadow, color and value, and all the way to the finishing step of grading the film.”

The camera, although virtual, is “mathematically true… to a real camera,” Lin said. “It has lenses, focal length, F-stop, lens distortion, and depth of field. And we mimic the camera movement: like a real camera it can be on a track, dolly or crane, or be a Steadicam or hand-held.”

One of the first steps in the production process is “staging.” “Staging is the choreography of the camera and the subject, and how we move them through the scene. We are responsible for framing and compositions. We need to do camera and character blocking. Determine positions and movements for both camera and characters. And we also establish the eye lines, screen directions and a load of other stuff too,” he said.

Like a d.p. in live-action, Lin has to decide on the type of lens to use (wide-angle or long lens), the type of shot (an over-the-shoulder, single, and so on), whether the camera should be moving or still, and if moving, what type of movement it should have. All this Lin referred to as “camera structure.”

“Camera structure is a way of organizing all those visual elements into something coherent to support your story and your characters,” he said. “So on ‘Inside Out’ we have three main parts to our camera structure: camera language, visual intensity progressions, and scale progressions.”

He explained that the camera language on “Inside Out” helps differentiate the two worlds in the film: the world of the mind, inside, and the human world, outside. “What we love about these two worlds is the contrast between them, and so we designed two separate camera languages that can help define and separate these two worlds, but at the same time contrast each other,” Lin said.

The outside world is based on real locations, San Francisco and Minnesota, “so the camera should feel real, with imperfections,” he said, while the inside “mind world” is imaginary, so it is “virtual and perfect.”

One way that these “imperfections” were achieved was to incorporate lens distortion, which added texture. Pixar had lens distortion ready to deploy for “Ratatouille,” Lin said, but due to a change in director it was decided not to use it, so the images were “flat.” Lens distortion was first used on “WALL·E.” The outside world camera in “Inside Out” was based on the S4s lens, with more distortion, and the inside world camera was based on the Ultra Prime lens.

Another way that they introduced imperfections into the outside world was by incorporating out-of-focus shots, just as in live-action when the focus puller misses the focus.

Another way to differentiate the two worlds was through differences in camera movement. In the inside world, more mechanical camera movement was deployed, using dolly, track, crane and boom. The movement is deliberate, graceful, controlled and based on a pre-determined pattern, Lin said. For the outside world, they wanted to use “something a little more organic,” such as using zoom, Steadicam and hand-held cameras. This is a little more loose and free, with no pre-determined path.

Lin’s team also supported the “emotional journey” of the central character, Riley, through a difference in camera movement in the outside world. In the first act, where her emotions are under control, Steadicam is used, and in the second and third acts there’s a shift to hand-held, as her emotions go out of kilter.

Scale progressions — scale being the size of the world from the perspective of the central characters — is used to support the development of the characters and storylines of Riley and Joy.

“When Riley is growing up her world is very wide and big. She is in Minnesota — the possibilities are endless,” Lin said. So, wide shots, giving more space around Riley, are used in act one, with strong horizontal and flat lines in the background. “In act two, when Riley arrives in San Francisco, her world becomes smaller and smaller.” More vertical and diagonal lines are used in the background, and Lin used the frame to “squeeze her a little bit” — using almost all medium shots.

Staging is also used to support the story. In early scenes, Riley is confident of her place in the world, and so she is always shown in the center of family scenes, with her mother and father on either side. Later in the story when she feels disconnected, she is shown to one side of her parents.

Framing is also used to support the main theme of the movie, which is growing up. Tight close-ups are reserved for the adults early in the film, but later, when Joy learns that Riley needs more emotions than just her, a close up on her face is used to show that she has begun to grow up. The same use of the close up is used with Riley to show that she has started to grow up.