SoftImage camrera's field of view (english)

The SOFTIMAGE 3D camera's field of view (FOV) is measured with the vertical lens angle, not the standard horizontal lens angle. Therefore, if you need to use the SI3D camera data for other purposes, you must first convert the vertical lens angle to the horizontal lens angle and then use the data.

To get the proper FOV for a particular shot you must know: lens focal length (55mm, 80mm, etc.), media (35mm film, 16mm film), and type of camera (vistavision, 4-perf, still, etc - since one type of film is used differently in different cameras).

Use the following formula to calculate the horizontal and vertical angles when you know the focal length, and either the width, or the height of the exposed surface of the film:

Horizontal angle = 2 * arctan (width/(2 * f))

Vertical angle = 2 * arctan (height/(2 * f))

For the conversion formula when you do not know either the horizontal angle, or the vertical angle, search the Knowledge Base for article Q167242.

The following table lists the vertical angle for the most commonly used 35mm SLR still camera lenses:

Lens SI angle

24 mm 53

28 mm 46

50 mm 27

85 mm 16

105 mm 13

150 mm 9

210 mm 6

A great source is the American Cinematographer Manual - it contains tables with the typical FOV's for different cameras and lenses. To use these in Softimage, you would divide the numbers by the aspect ratio (to get the vertical field of view).

SoftImage camera's field of view