by Tony Karp

Zoom lenses, Pan heads, and Computers, Oh my!

This simulation shows the possibilities of programmable PT-ZIF cine equipment. This three-part move is done in one continuous take, with the camera in a fixed position.
It's all about PT-ZIF and programmability.

PT is Pan, Tilt, changing the aim of the camera.

ZIF is Zoom, Iris, Focus, changing the view of the lens.

Programmability lets the director or cinematographer set up moves that are precise and repeatable.

Let's talk about pan heads.

First, you have the Worrall-style geared heads. I saw my first geared head back in 1959, when I was shooting for NBC in NYC and Hollywood. I didn't get to play with one until I worked on TV commercials in the 1960s. They made it possible to work with heavy cameras. The geared head made it easy to aim the camera, but making an actual move using the wheels was outside my skill set.

The other main style is the OConnor-style head, which uses a handle to aim the camera, and a damping mechanism such as a fluid to smooth out the moves. Most tripod heads are based on the OConnor model, but only the ones designed for cinema shooting have a damping mechanism. Making a smooth move with an OConnor head was also outside my skill set.

Both types of pan heads can be motorized, but the result may be sub-optimal.

A third type of pan head is the remote-style motorized head. These heads are found on locations as diverse as the top of cranes or jibs or booms, and on the floor of a TV show. With these heads, the camera is in a mount that tilts up and down, while the base rotates to provide panning. In these setups, the camera will also be under remote control, both for the operation of the camera, and to adjust the zoom, iris, and focus on the lens.

It's the remote-style setup that lends itself to programming.

Now let's talk about lenses.

I like zoom lenses because they add another tool for the filmmaker. Zoom lenses can be motorized to control zoom, iris, and focus remotely. Combining a zoom with a pan or tilt creates a new type of move that would be difficult to do with current cinema equipment.

So, in some ways, we already have all the piece-parts needed to make PT-ZIF moves. Unfortunately, like the Scarecrow on the way to Oz, it really needs a brain.

It's the programmability that combines the pan and tilt with the zoom to make moves that can be set up by the director or cinematographer using keyframes to mark the key points in the move. Programmability gives the ability to set up multiple moves that are shot as one continuous take.

 - Zoom lenses, Pan heads, and Computers, Oh my! - - art  - photography - by Tony Karp - Discovery Technology - Cinematography - The Godfather - Designing the Future -
Dr. Harold Edgerton, inventor of the electronic flash, photographed by Ben Rose, using a programmable, multi-axis system I designed and built in 1978. It had pan/tilt/zoom/strobe, controlled by a digital computer using a programming language that I called PISCAL.

This is an example of a pan combined with a zoom -- Pazoom!

Where to begin?

The problem is that the pan head is made by one company, the camera by another, the lens by still another, and don't forget the company that makes the motorized gears that drive the lens's zoom, iris, and focus. And, there are multiple companies making this sort of gear, each with its own unique interface. Getting all of this diverse equipment to work together presents some real challenges.

But this is taking a geek's viewpoint of the problem, starting at the lowest level and working upwards. Not quite sure where you're headed.

Better to take a guru's viewpoint and start at the highest level. Here, there are no limitations. Think of an ideal world. Better to know where you want to end up before you begin. Starting at the highest level, then working downwards will yield better results.

Now think of what the interface to this ideal system would look like and how you would tell it what to do. Actually, there will be more than one interface, each designed for a particular person.

Here's an incomplete list:
Director's interface

Keyframes - Framing the start, framing the finish, and setting the time for the move. Keyframes can be strung together to create complex moves.

What sort of controls will be needed to set up keyframes? For framing, you need a way for the director to operate the pan/tilt head, and the zoom lens. There will be multiple variations on this, as some prefer joystick controls, while others might choose one based on knobs or a touchscreen interface. The same goes for the controls used to set the timing of the move.

Running the keyframes in real time, then editing them until they're just right.

There will be a facility for keeping track of the keyframes, and saving, restoring them as well.

Simulator link - View the moves previously designed on the Cine-simulator. Use the simulator and its measurements to set up the actual scene.

Cues - Relative to keyframes, or relative to the timeline, these are independent actions such as lighting cues, actor cues, effects cues, etc.

Camera operator's interface

Access all of the camera's controls in a single interface.

Check and edit things like camera profiles while looking at the actual scene.

Save, retrieve, and edit settings profiles, based on scene.

Zoom-puller's interface

If the zoom lens is the only programmable device being used, there will be a separate, simpler control for the zoom puller. It would probably look something like the interface shown below.

An interface like this would allow the director to program and try out different zoom moves, but the zoom puller could run the zoom during the actual shot.

With all the computer power made possible by the technological advances of the last fifty years, there would now be a facility for storing, retrieving, and editing moves. It would also have the ability to string several moves together.

Focus-puller's interface

Autofocus - While some cameras have autofocus abilities, it will be up to the focus-puller to decide where the autofocus should be aimed at any particular time.

Programmed focus - With programmable moves, the distance from the camera to various items and people in the scene are calculated in advance. The focus-puller can easily decide where the focus should be at any point in a move.

Real time focus - A touchscreen interface, operated with finger or stylus. While viewing what the camera sees, the focus-puller can touch an area of the screen to direct the focus.

This is just a preview of the possible interfaces. Since the design is modular, functions can be moved between interfaces, or used to create new interfaces.

Also, as things progress, other functions can be added to the list of programmable things. For instance, the helicopter in the scene above is actually part of the background on a large LED virtual environment. The director will be able to set up a cue to it using the director's interface.

Still to come is a discussion of the intermediate levels of the system, where we describe the APIs and drivers used to direct the actual hardware devices.

 - Zoom lenses, Pan heads, and Computers, Oh my! - - art  - photography - by Tony Karp - Discovery Technology - Cinematography - The Godfather - Designing the Future -
This is the programming interface for the computer control that shot the opening scene of The Godfather. Using this interface the director or cinematographer could program a zoom using the simple controls.

I'm building a simulator

The programmable PT-ZIF equipment I've described doesn't exist, so there's no way to test my ideas in the real world. I'm going to need some sort of cinematography simulating software. Bad news: While there are cinematography simulator programs that can model movie sets and some actors movement, there are none that can actually simulate a series of programmable moves.

So I'm building a simulator. It will use realistic field of view/focal length, distances, and timing. Measurements will be accurate.

The video at the top of the page was produced by the simulator as an example of what you can do with programmable PT-ZIF equipment. It was simulating a Sony ILME-FR7 with the 28-135mm kit lens, along with a Discovery Technology Cine-Brain control system.

Important note

The programmable PT-ZIF equipment I've described here is not meant to replace any existing cine equipment or technique. The goal is to expand the vocabulary of cinematography by adding new possibilities for storytelling.

Why I called this meeting

Fifty years ago, I designed and built the programmable zoom controller that was used to shoot the opening scene of The Godfather. At the time, building it seemed like an impossible task, but somehow I found the answers. It gave the guys who shot the Godfather a new tool that made the opening scene possible.

Now, fifty years later, it turns out that this was the only programmable zoom controller ever built. In spite of all of the technological advances since then, that's it. So I guess that this makes me the world's foremost authority. By default.

Today, this is an opportunity to build something new. It's an opportunity to add new camera moves and storytelling tools.

I'm 83 years old, and I've long since hung up my soldering iron. But I still have all of the knowledge that it took to build the original, and lots of plans for the future.

Surely, there must be folks in the cinematography equipment industry who are looking to build something new. A new set of tools that will extend the vocabulary of cinematography.

Arri, are you listening?

Angenieux, are you listening?

Sony, are you listening?

Copyright 1957-2023 Tony & Marilyn Karp