3D Movie Calculator

3D Movie Calculator calculates the correct interaxial from a small set of parameters.

3D Movie Calculator is the stereographer dream. This smooth and simple app calculates the optimal distance between the two cameras in a 3D shoot. Having this on your iPhone allows you to work fast and precise on a movie set, aligning the perfect setup for any shot in seconds. 3DMovieCalc is designed to be used for shooting 3D Movies with professional equipment like the Arri Alexa, the SI2K, RED One, F35 and similar top of the line digital film cameras, but will also work for still images.

BACKGROUND: HOW 3D MOVIES WORKS

When the audience watches a 3D movie in the cinema, they see two images at once, one image with the left eye and the other image with the right eye. The brain fuses the two images into one, with added depth perception. Basically, the brain finds similar textures in the images, and the relative distance between the textures tells the brain something about the distance to the object.

When we create 3D movies for cinemas, we exploit the stereopsis depth clue to create an understanding of depth in the brain. But because stereopsis only "works" within the closest 10 meters to the viewer, we can only create an image thats 10 meters deep for the viewer. Further than 10 meters away, the eyes see in an almost parallel direction, and therefore the brain switches to other depth clues.

When audience look at the screen in the cinema, they will converge their eyes on objects or textures that are the same in both images, so by shooting the pictures correctly, we can control the convergence of the eyes, and thereby the depth perceived. We do this by tuning the distance between the cameras - the interaxial distance - to create the depth for each shot that we want.

For a natural depth that is pleasurable to watch, the interaxial distance has to be correct for the depth we are shooting. If the interaxial is not correct, we force the eyes to either look further apart or more crossed then whats natural for the shot, and this causes a strain on the eyes.

HOW 3D MOVIE CALCULATOR WORKS

3D Movie Calculator calculates the correct interaxial distance (sometimes referred to as intraocular distance) from a small set of parameters.

As you can see below, the interface is very accessible. The primary inputs are the far and near distances of objects in the scene and the settings of the camera – lens focal length, camera sensor size, the size of the screen you are shooting for (a cinema screen is approx 12 meters wide) and the amount of depth effect you desire.

For a correct, naturally viewable depth, set effect to 1.0X. But you may choose that this movie just needs a small amount of depth, or that it needs a bit more depth for some shots than others, the effect input is where you set your preference.

If you don’t know the size of the sensor of the camera you are using, press the “Cameras” button and most likely your camera is there. If not, google it.

On the Preferences screen, you can also change the display units to be either Metric or Imperial.

On the main screen are two inputs, the far point and the near point. The far point is the distance to the furthest away object in the picture. If this is really far away, like mountains in the background, you should set it at something like 2000 meters.

The interaxial output is the correct distance between the cameras for the shot you have setup.
The convergence output tells you how far from the screen cameras axis should meet – this is where you want your main subject and focus to be in the shot.
For more information about 3D Movie Calculator, have a look at http://www.3DMovieCalc.com