How to build a 3-D movie camera
Easy, low-budget solutions to filming 3-D

Rambo shooting 3-D from the hip - The Michael Riley 3-D mirror setup on a Doiflex 16MM camera

Another very simple solution - Creating a wider interaxial but also more control

One Simple 8MM Film Camera plus two mirrors - D.I.Y. 3-D

 

Simply putting two cameras side by side Sure, it's simple enough to put two cameras side by side, but the distance between the lenses will simply be too big, resulting in miniaturized scenes and, for closer shots, unfusable 3-D. So a solution is needed to get the lens axes closer together: to reduce the interaxial distance. The professional solution is to use a beamsplitter with semi-silvered mirrors, but when you're short for cash, you may want to have a look at the following D.I.Y. solution:

The Kalashnikov of 3-D movie cameras:
The S.P. Ivanov / Michael Riley / Adam Ross 3-D solution
Images supplied by Adam Ross. 3-D 16MM film camera with anamorphic lens built by Adam Ross.

As first constructed by S.P. Ivanov in 1940, later featured in PhotoGraphic magazine of 1977 by Michael Riley and very kindly brought to the 3-D Revolution's attention by Adam Ross, the following construction is that of the perfect no-to-low-budget 3-D camera. That means YOU can start filming in 3-D about an hour from the moment you have managed to find the required components (basically after the glue has dried).

Please note that this system can be used for 3-D image filming/ recording that can then be post-processed to be presented in any desirable format. This can be anything from anaglyphic presentation to field-sequential television presentation or polarised projection. But to present this material directly without any post-production, projection with a film-projector or a one-lens beamer through polarising or anaglyphic colour sheets must be employed.

What you will need

- A video or film camera
- A clipboard or other stiff board or plank that can be drilled
- Two small mirrors: preferably front surface mirrors
- Two bookends or other 90 degree fixtures
- One or two small hinges
- Glue: preferably epoxy glue (2-component glue) or superglue. Watch those fingers.
- A bolt and wing nut to secure the camera

- To film in a 1.33:1 (4:3) ratio (perhaps masked down to 1.77:1 (16:9) or wider) in stead of a 0.66:1 (2:3) ratio, a 2x anamorphic lens must be employed.
If you intend on projecting straight from your source material, the lens must be of the type intended for both photography AND projection. A theatrical projection lens alone will not work, for it usually cannot focus closer than 20 or 30 feet (6 or 9 meters).
A good suggestion for film is a Kowa 16-H 2x lens, which focuses down to 5 feet (1,5 m). These lenses are very common used, and seldom cost more than 200 dollars. You may be lucky enough to buy one for, say, 75 dollars from a cine dealer (or good old Ebay).

How to make the Camera Assembly

Use epoxy to glue metal hinges onto backs of bookends. Leave a 1/8-inch (3 mm) gap between bookends; let paste harden.

Draw a line lengthwise down centre of clipboard and position bookends on clipboard as shown in the photo. The joint between them should be over the centre line, and both should be at a 45° angle to the centre line.

Glue bookend that will be closest to camera firmly to clipboard. The other one should be left unglued so it can be repositioned when clip is raised.

Glue mirrors to bookends with epoxy paste, leaving a gap between the two mirrors equal to the thickness of one mirror. Use large dabs of epoxy so that mirrors can be aligned before glue hardens.
Alignment can be checked by swinging the movable mirror (the one whose stand is under clipboard) back until both mirrors form a flat plane.
Hold a ruler horizontally up to mirrors so that its reflection is visible. Then note where ruler's reflection crosses behind mirror joint. If ruler appears broken - that is, if the reflection in one mirror is slightly higher than in the other mirror - then one of the mirrors must be leaning away from you more than the other.
Squeeze bottom edge of that mirror forward until edge reflection of ruler appears as a straight line.

Attach movie camera to clipboard with a (1/4-20) bolt and wing nut. Camera must be positioned so that its lens is directly over centre line and aimed toward joint between mirrors.
Distance from camera's focal plane (in case of a film camera the place where film is when it is being exposed) and mirror joint should be 8 inches (20,3 cm).

How to adjust Convergence distance

The convergence distance is the distance from the mirror joint of camera assembly to where the mirrors' two fields of view converge (see illustration No.3). It should be adjusted correctly in order to avoid eyestrain or double images when the film is viewed.

For most of your filming the convergence distance should be nine feet (2,75 m). This is called fixed convergence. It gives the most realistic picture, and it can be used whenever the subject matter is more than five feet (1,5 m) from the mirror joint.
For close-ups the convergence distance can be temporarily shortened: this is called variable convergence.

To set convergence, first position camera on clipboard so that mirror joint appears in exact centre of viewfinder. Then place an object nine feet (2,75 m) from mirror joint.
This object need not be something that you intend to film. It is used merely for a reference point to help make convergence adjustment.
Aim camera assembly so that object just touches left-hand side of right-hand picture in viewfinder.

For fixed convergence adjust the zoom lens, if you have one, to the widest possible angle (zoom out as far as possible). Then make the convergence adjustment by changing the position of the No.2 mirror.
For variable convergence the convergence adjustment can be made either by adjusting the No.2 mirror or the zoom lens. Either of these methods will cause the object in the right-hand picture to remain in position while object in picture on left will move either closer to or farther from the left side of picture.

Make your adjustment so that object just touches left side of both pictures.
If your camera is not a reflex, you will have to make your convergence adjustment and then reposition camera on clipboard so that the taking lens is aimed directly at mirror joint. For best results this should be done as accurately as possible.

Test Pattern

Before shooting each roll of film or tape of video, place an object nine feet (2,75 m) from mirror joint of camera assembly. Centre object in either one of the pictures in the viewfinder and shoot a few feet of film or a few seconds of video. This part of the film will be used later as a test pattern to line up projected images.

Filming in 3-D

Filming in 3-D is not exactly the same as filming in 2-D. The first thing you'll have to get used to is aiming the camera.
When you look straight ahead into the viewfinder, the mirrors will show you a picture of something that is off to your left. If you're not using a tripod, you should practice aiming the camera before shooting any film. In 3-D you have to avoid using a lot of fast cuts. You should especially avoid cutting back and forth between a distant subject and a close-up one. This is because it takes time for an audience to adjust to sharp changes in depth. You should also pay attention to the amount of depth in each scene. Subject matter that is shallow to begin with will also look shallow on the screen. When an object comes closer to the camera than about five feet, you should use the recommendations for super depth.
Read more about filming in 3-D in the 3-D Script to Screen section.

Off-the Screen and In-your-Face 3-D

It seems that almost every 3-D movie has at least one scene where bats, arrows, landslides, etc., seem to come right off the screen and out into the audience.
The secret for creating this type of illusion is to use a small object and bring it close to the camera without letting it touch the edges of either picture in the viewfinder. This is because the movie screen appears to be a window through which the action can be viewed.

Another aid to creating this type of illusion is to have the background the same distance from the camera as the convergence distance. This is to establish reference points so your eyes can compare the near object with the background. When these rules are followed, each member of the audience will see the object coming directly toward him. If the object is small enough, it can be moved to within about four inches (10 cm) of the mirror joint without touching the edges of either of the two pictures in the viewfinder. A member of the audience will then see the object as being about 12 inches (30 cm) in front of his or her face.

Upon experimentation you will soon find acceptable distances and convergence settings. However, do remember that the larger the screen a 3-D film is projected on, the bigger the parallax will be. So the eyes of the audience have to work harder to fuse left-eye and right-eye image. Hence an out-of-the-screen effect that looks perfect on a television screen (normally used on film production for playback) may not work at all on a film screen, let alone an IMAX screen.
Read more about this in the 3-D Script to Screen or the 21st Century 3-D section.

3-D Projection

With projection, image separation can be achieved by using polarising sheets and glasses or anaglyphic (red-blue) sheets and glasses. The latter is sometimes called dichromatic because one uses two opposing colours as filters.
For other projection solutions, check out the 3-D Script to Screen section.

Image used for mirror-projector alignment

How Hollywood does it

StereoVision, Arrivision, Optimax III, SpaceVision. Plenty of different systems have been devised to service the Hollywood film industry's 3-D efforts.
These systems were mostly built to perfection and trying to improve on them may be noble, but slightly pointless. They are affordable systems ready to be used and proven in the field.

Patent drawing for the Laikin over-under 3-D lens adapter system

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