20 THREE-DIMENSIONAL PHOTOGRAPHYNow before we go on to the imported cameras, there is one
inevitable question which must be answered here. There are now
three high-quality domestic cameras available. Which is the best?
The one which you choose and use.
Look at all three, handle them, examine their features. Then
choose the one which appeals to you the most. All will give excel-
lent results. No matter which you buy, by the time you have given
it a thorough tryout you will be ready to swear that it is by all
odds the best stereo camera ever made. The writer has used a
Realist, Personal and Verascope since their initial appearance and
has no criticism to offer. All are excellent cameras. No doubt the
same could be said of the Stereo Vivid were it not for the simple
fact that no advance model is as yet available for test. By reason
of its similarity in general design to the Personal, the writer fully
expects it to share the same high quality of the three cameras
which he has actually used over relatively long periods of time.
Interlocking Images.-Naturally, unless a great deal of film is
to be wasted, the stereo pairs cannot be kept separate when tak-
ing. In one sequence as used by Realist and Personal cameras,
they are intermingled in such a way that the film cannot be cut
at any point without dividing a pair. This is of no consequence
when the images are to be individually mounted, but for viewers
using strip films, such procedure means the loss of one picture
at each cut. It is also used in the Vivid.
This interlock can be easily understood when the "lefts" and
"rights" are considered separately as shown here:
Left Exposures, 1 - 2 - 3 - 4 - 5 16 - 7-8-9
Right Exposures, 0-1-2-3-4-5-6-7
Interlock
Sequence, 1-0-2-1-3-2-4-3-5-4-6-5-7-6-8-7-9
This normal interlock used in the three cameras just described,
is based upon the so-called normal sequence in which there are
two images between each stereo pair. European cameras includ-
ing the Iloca and the Verascope 40 make wider images and have
but one image between each pair, so their interlock sequence is:
1-2-1-2" 3-4-3-4" 5-6-5-6" 7-8-7-8" etc. It will be noted that
this film may be cut at any point marked * without injuring a
pair. This interlock is accomplished by having a film transport