226 THREE-DIMENSIONAL PHOTOGRAPHY
It is well known that stereographers are warned repeatedly to
keep the camera level from side to side. The stereo camera may
be pointed upward or downward somewhat, but never from side
to side, that is with the two lenses off level.
This rule is deliberately violated in making angle shots, but
other conditions must be such that this can be done without spoil-
ing the shot.
A second factor is a physio-psychological one. If you see a tree
cut down it does not look as it did when standing. You may stand
at the butt and look along the length of the trunk but the ap-
pearance is wholly changed. There is a certain psychological-
visual effect gained by lifting the head to look upward or bending
forward to look down. Undoubtedly this has some close connec-
tion with the matter of balance.
This, too, is taken advantage of in making shots upward and
downward. If you stand near a tree and shoot directly upward,
the slide has little effect when viewed naturally, but if you lift the
viewer so the head is tilted backward and the eyes turned upward,
the vertical appearance is astonishingly convincing. However, as
this demands cooperation on the part of the observer we shall
leave it with this mention, and return to the true angle shot.
An excellent slide of this type was sent to us recently. The
location was in a Western National Park. The terrain was of
rugged hills and immense boulders scattered about. The stereog-
rapher (F. W. Kent) had posed his model so that she leaned
toward a huge boulder at an angle of some 45 degrees, supporting
herself by an arm stretched out against the boulder. The camera
was tilted so that her body was parallel with the sides of the
finder and the exposure made. The result was astounding. There
was a perfect stereogram of a young girl, nonchalantly supporting
with one hand a boulder some fifteen to twenty feet in diameter
which hung over her with no other support than her hand! It
was wholly convincing.
Of course there is a trick to it, and it is this: The subject must
be so arranged that there is nothing whatsoever in the picture to
indicate the camera tilt. In the stereogram just described, model
and boulder were silhouetted against the sky. Had there been a
tree or a mountain cabin or other normally vertical line in the
composition, its tilt would have spoiled the whole thing.