How to build a 3-D movie camera
Easy, low-budget solutions to filming 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
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
- 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
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).
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
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.
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 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 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.
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
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
3-D animated still from 'Jaws 3-D' with left-eye and right-eye image alternating.
With the Arrivision 3-D lens adapter used for this shot, image distortion is clearly taking place - most notably in the bottom- left corner.
Using mirrors and lenses, this is an unavoidable fact of 3-D lens adapters. However, these distortions are unnoticeable to the viewer unless they are severe.
3-D animated still from 'Dial M for Murder' with left-eye and right-eye image alternating.
Using two separate cameras can lead to other 3-D image problems; in this case the left-eye camera is positioned slightly forward in relation to the right-eye camera. This can be due to any misalignment or perhaps the cameraman pointing the right-eye one of the converging cameras straight at the subject. The cameraman will in this case have used the right-eye camera viewfinder only and not a combined viewfinder.
Contact 3-D Revolution Productions
Tel +44 1179 441 449
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