ANGLER

Comparisons are constantly being discussed about the visual differences between movies (big) and TV (small). Unless one has unusual sitting preferences, the difference probably is not what it appears. Darkness is illuding.

The size of an image is totally governed by its visual angle , not by the absolute size of the object viewed. The visual image of City Hall, seen from Olympic Boulevard, is smaller than one’s thumb at arm’s length.

In four theaters I’ve measured, the average distance from the screen to the center of the audience (about three-fourths back) was about 60 feet; the screens themselves looked to be about 15 feet high. Thus, a person seated in the middle of the audience would see an image represented by the height/distance angle 15/60 (feet). If this person has a 27-inch (diagonal) TV set and views it from five feet away, he would have a viewing angle of 18/60 (inches). The image in the living room is actually larger than the one in the theater.

ALLAN E. EDWARDS

Sherman Oaks