Build complex toys and simple tools
by Tony Karp

Doing the impossible - Part 2 - The challenges
< Previous Jun 26, 2007 Next >

zoom lens - Doing the impossible - Part 2 - The challenges -  - The Godfather - computer controlled zoom lens - Analog Computer - - Tony Karp, design, art, photography, techno-impressionist, techno-impressionism, aerial photography , drone , drones , dji , mavic pro , video , 3D printing - Books -
This is what the Angenieux 25 - 250mm zoom lens looks like in its unmotorized form. It's quite large and quite heavy, weighing over ten pounds. The two rods are attached to the camera and run underneath the lens to support its weight. This is the bare lens with no zoom control attached.

Here are some of the design and philosophy issues that were involved in the design and building of the computer-controlled zoom lens used to shoot the opening scene of The Godfather.

Where no man has gone before - It would have been nice if someone else had already built a computer-controlled zoom lens. Then I would have had some guidance, and could have just worked on building a better model. But no one had. I would be the first. In fact, my zoom control was probably the first piece of computer-controlled equipment ever built for motion picture use. So, Like Captain Kirk, I ventured forth.

Artistry - There were some controls for zoom lenses available at the time, but they were very simple. A typical one was fitted to a small handheld box with a little lever that did the actual controlling. Push the lever a little bit and the lens zoomed forward slowly. Push the lever a little bit further and the lens zoomed faster. Push the lever in the opposite direction and the lens zoomed in the opposite direction. That was it.

So it's no surprise that anyone who could produce exactly the zoom that the director or the cinematographer wanted was highly sought after. Zoom lens operators might be booked several pictures in advance. They were considered as artists for this ability. But even with all of this skill, the best that could be hoped for was just an approximation of the desired zoom. The use of the zoom lens in motion pictures was limited because of these problems.

Repeatability - It's one thing to do a zoom, but it's something else entirely to be able to repeat exactly the same zoom again and again, take after take, until the director is satisfied with the result. The characteristics of an ideal zoom would be to hit the start and end points accurately, and to make sure the zoom would take exactly the right number of seconds, every time.

With the old zoom controls, you would fiddle with the little lever until the starting point for the zoom looked pretty good, then mark that on a piece of tape around the lens. Then repeat the process for the framing at the end of the zoom, and make another mark on the tape. Then fiddle countless times until you got the right time for the zoom between the two points and make a mark on the zoom control showing how far to push the little lever. It was a long and complicated process to set up any but the simplest zoom.

Room at the top - This was always a sore point with both the director and the cinematographer. They wanted to be able to set up the zooms themselves. The framing at the beginning and the end of the zoom is critical, as is the time it takes to get between the two points. You would rehearse the actors multiple times and then measure the time with a stopwatch. This would tell you how long the zoom should take if it was going to match the speech.

Wouldn't it be nice if the director or cinematographer could just look through the camera, set the start and end points for the zoom, and then, somehow, set the time that the zoom should take? Wouldn't it be nice if the zoom could be repeated any number of times, producing exactly the same zoom at the touch of a button?

For this, you needed a computer, and this is where I was headed.

Infinite speed range - It would be nice if the zoom control could do a very fast zoom -- say half a second from end to end. And it would be nice if the same control could give a zoom that went on for minutes, as in the opening scene of The Godfather.

This is a problem I didn't even think about when I started. The existing zoom controls had a very limited speed range. You might have a range, for a full zoom, from several seconds to about thirty seconds. Zoom lenses required a lot of torque to turn them, and this required small, powerful motors. But motors of this type had a limited range of speeds.

I would be using a similar motor in the zoom control I was building, and I would have to find a way around this limitation.

Soft start and stop - This a little something extra. Instead of an abrupt start and end to the zoom, it would be nice to have a soft start and stop. If done properly, the start would be imperceptible, and the end of the zoom would be equally smooth. There should be an adjustment for this softness, from none to maximum.

Computer - In 1968, computers that could do the sort of real-time processing that would be needed to control a zoom lens were the size of a refrigerator, drew thousands of watts, and needed very complex assembly language programming. Obviously, I would be headed in another direction. In the end, I designed a computer to control the zoom lens. It weighed less than two ounces, measured less than 3 x 4 inches, and drew only a few thousandths of a watt of power.

Motor control - The motor control would have to be solid state, using minimum power for the longest battery life, and be capable of driving the zoom lens over an infinite speed range.

Portability - Easy to carry and easy to set up - The control unit that would program the computer would be handheld and should weigh about a pound. The power unit with the batteries and the motor control circuits should weigh less than ten pounds. On the movie set, the system should be easy to set up and easy to break down at the end of shooting. In addition, there would be cables hooking the system together. There should be no way to put things together incorrectly.

The lens with its attached motor, the computer unit, the power unit, and all cables should fit into a padded, easy-to-carry container that would be as rugged as any piece of movie equipment.

Interface - Here, in the twenty-first century, computer interfaces are very advanced, with touchscreens, mice, and computers that respond to human speech. When I built the zoom control, there were no computer interfaces, other than a primitive display terminal or a Teletype terminal. The interface for the zoom control would have to be easy to use and shouldn't require any special training. It would have to be intuitive, so a director or cinematographer could easily program even a complex zoom.

Quite a requirements list, and there would be many more hurdles along the way.

Part 3 will tell about some of the solutions to these problems.

< Previous Jun 26, 2007 Next >

Copyright 1957-2021 Tony & Marilyn Karp
Web Site Design
Systems Design
The Future
Recent Entries
Some pictures from my smartphone
My fix for bird strikes on my window
Goodbye, Columbus
At an old curiosity shop in Purcellville
Smartphone vs camera -- Why you need both
Raw vs JPEG with the P30 Pro's super-wide camera
At the Air and Space Museum with a Huawei P30 Pro
A tribute to the architect, I.M. Pei
A blast from the past - Music's golden age
Green eggs and ham. And onions. And cheddar.
A blast from the past
Hidden views -- Discoveries from my drone
Will the FAA stop regulating hobby drones?
Here's a panorama from my Mavic, and two more
A quadcopter is a totally new kind of aircraft
Taking to the air -- First flights
Let's talk about the Mavic Pro's camera
A different viewpoint
The value of time in the creative process
Variations on a skink
Andy shoots raw. Ann always shoots JPEG
A butterfly in Havana -- From start to finish
Recovering highlight detail in JPEG images
A tribute to Paris on November 14, 2015
Some black and white pictures from long ago
Panasonic DMC-ZS40 pictures - Part 2
Panasonic DMC-ZS40 pictures - Part 1
Art in the 3rd Dimension -- A butterfly takes wing
Shooting for NBC
What's new at the zoo?
On being a photojournalist
Some pictures of Manassas
Finishing a picture
Watching the sunset in Adams Morgan
A night at the circus - 1966
Fortune Qwerkies (tm) -- Fortune cookies for the smartphone user
Art in the 3rd Dimension -- The evolution from flat to solid
Art in the 3rd Dimension -- Showing how the pieces fit together
Getting a grip on the Panasonic DMC-LF1
Some random thoughts about the Panasonic DMC-LF1
The Panasonic DMC-LF1 is a game-changer
Art and the Zen of QR Codes -- Making QaRt
A new process for printing art in the 3rd dimension
Bubbles! Bubbles! Bubbles!
Photographing the Perry Como Show
Hiking at Sky Meadows with my Panasonic DMC-ZS20
Working for the union
A new take on JPEG vs raw - Panasonic DMC-ZS20
Some pictures from my Panasonic DMC-ZS20 - Part 2
Some pictures from my Panasonic DMC-ZS20 - Part 1
My new go-everywhere camera - Panasonic DMC-ZS20
My brief life in the studio
Shooting Shakespeare - The Tempest - NBC, 1960
Impressionist bees
In the studio with Roz Kelly
At the Peppermint Lounge - 1962
An evening with Gene Kelly
A portrait of Donna Mitchell - Variations on a theme
The "Sky Dream Ultimate" plug-in from Wilkington-Smythe
Post-processing: Going from good to great
Winter pictures from my Panasonic DMC-FZ150
Using the Panasonic DMC-FZ150's "Photo Style" Menu
A valentine for the Artist's Muse
The Panasonic DMC-FZ150's controls
Some thoughts on the Panasonic DMC-FZ150 - Part 2
The Panasonic DMC-FZ150 - A cure for DSLR envy?
Some thoughts about my Panasonic DMC-FZ150 - Part 1
The Panasonic DMC-FZ150 -- Best camera ever?
Sunglasses - What can you add to a picture?
Hey, camera makers. If my smartphone can do this
The Artmuse Variations - a look inside my new book
A tribute to George Washington on Veterans Day
A visit to the White House
The little farmhouse, the tractor, and the interesting tree
Buckminster, the baby buckeye butterfly
Memories of September 11
Happy Corporation Day!
A trip to Monterey and San Francisco
The first battle of the American Civil War -- 150 years ago
The end of an era -- The last American manned mission
Growing an Italian stone pine tree
Random thoughts on art and other stuff - From my new book
Playing with a classic - Sony DSC-R1 - Part 3, Warrenton
Playing with a classic - Sony DSC-R1 - Part 2, In the house
Playing with a classic - Sony DSC-R1 - Part 1, Winter
Some recent pictures
Fixing a Panasonic DMC-FZ18/FZ28/FZ35 problem
Into the world of shadows
A walk through Warrenton
Partly moony with my Panasonic DMC-FZ35
My new Panasonic DMC-FZ35 - Part 3 - Video
Some pictures from my Panasonic DMC-FZ35 - Part 2
Happy birthday to muse...
Pixels and parking lots -- The Panasonic FZ35
Some pictures from my Panasonic DMC-FZ35
My new Panasonic DMC-FZ35 - Part 2
My new Panasonic DMC-FZ35 - Part 1
On our way to Warrenton
Evolution of an Iris
A new feature in Adobe Camera Raw 5.4
A tribute to the Apollo 11 astronauts
The pole dancer - Variations on a theme
Restoring lost highlight detail in JPEG images
A short course in photography in ten easy lessons
Kodachrome memories
A walk in the woods on my birthday
Mythbusters - More raw vs JPEG myths
Restoring lost shadow detail in JPEG images
Expose for the highlights, develop for the shadows
Something new -- Interchangeable cameras
Honey, I shrunk the newspaper - The "Nano" NY Times
Mistaking evolution for revolution
Some pictures from the artist's muse
Photography becomes art -- Daibutsu Buddha at Kamakura
Happy House-i-versary
25 random things about the artist's muse
It happened at the Met
Some pictures and some settings - Part 4 - DMC-FZ28
Some pictures and some settings - Part 3 - DMC-FZ28
Some pictures and some settings - Part 2 - DMC-FZ28
Some pictures and some settings - Panasonic DMC-FZ28
Noiseography -- A new photographic technique
Shooting infrared with the Panasonic DMC-FZ28
You're never too young
One month with the Panasonic DMC-FZ28
A trip to Berryville - Panasonic DMC-FZ28
It's the Hobbitt's birthday
On September 11th
Shooting Tri-X with the Panasonic DMC-FZ28
A shot in the dark - Panasonic DMC-FZ28
Sunset and the far-up lens -- Panasonic DMC-FZ18
Further musings on the Panasonic DMC-FZ28
Customizing your camera for high-ISO photography
Panasonic DMC-FZ28 vs DMC-FZ18 at high ISO
Some musings about the Panasonic DMC-FZ28
Hummers, SUVs, DSLRs, and my DMC-FZ28
Panasonic DMC-FZ28 -- At the Flying Circus
Panasonic DMC-FZ28 -- The journey begins
Farewell, my Panasonic DMC-FZ18
More about the settings for the DMC-FZ18
Dealing with the modes and settings of the DMC-FZ18
Photography becomes art - Bird on a wire
The artist's muse at sunset -- DMC-FZ18
Do you need fancy equipment?
Now here's my plan
Good cookie, bad cookie
But seriously, folks...
Post-processing Mr. Squirrel
A museum of one's own
We need new words to describe what's happening
Going over to the dark side
Shooting the moon
Happy Anniversary, Hobbitt
The view from my window - DMC-FZ18
My favorite museum
A toast to the artist's muse
The DMC-FZ18, a sunset, and a glass of beer
Remembering Herbert Keppler
Shooting abstracts with the Panasonic DMC-FZ18
Fixing a Panasonic DMC-FZ18 problem
More pictures from my Panasonic DMC-FZ18
The journey of a thousand Melvins
Stairway to the stars -- Extreme post processing
DMC-FZ18 - Raw vs JPEG - The JPEG Manifesto
Chromatic aberration and the DMC-FZ18
Raw vs JPEG, the DMC-FZ18, and a mystery
Some pictures from my Kodak P880 - Part 2
Some pictures from my Panasonic DMC-FZ18
Some pictures from my Kodak P880 - Part 1
DMC-FZ18 - Don't be afraid of the dark
Shooting in "Medium" - DMC-FZ18 - The right exposure
Shooting in "Medium" and the Panasonic DMC-FZ18
In-use review -- Panasonic DMC-FZ18 - Part 2
In-use review -- Panasonic DMC-FZ18 - Part 1
Photography becomes art - Fantasy at Ida Lee
Photography becomes art - The chefs at Little Washington
My new old camera - the Kodak Easyshare P880
Photography becomes art - Variations on a theme
Doing the impossible - Part 4 - The final result
Doing the impossible - Part 3 - The solutions
Doing the impossible - Part 2 - The challenges
Doing the impossible - Part 1 - The Godfather
All the (art) news that's fit to print
The museum becomes art - #1
Photography becomes art - Making an angel
How to test a camera
Hitting the wall
Extreme post-processing - Working with infrared
Blogging 2.0 - A new interface
A funny thing happened on my way to the blog
In the beginning...