Some unfavorable conditions are still deficiencies of the technique; for instance, the camera picture in some respects exaggerates the distances.

If we see through the open door of the rear wall into one or two other rooms, they appear like a distant corridor.

Moreover we have ideal conditions for vision in the right perspective only when we sit in front of the screen at a definite distance.

We ought to sit where we see the objects in the picture at the same angle at which the camera photographed the originals.

If we are too near or too far or too much to one side, we perceive the plastic scene from a viewpoint which would demand an entirely different perspective than that which the camera fixated.