Handbook of High Speed Photography - IET Labs, Inc.

The subject image will appear to move or jitter if the camera speed is
not stable. The rate of this image jitter will increase (or decrease)
depending upon the ratio of the camera and projector frame rates.
Figure 6-2. Movie of model airplane wing flexture resulting from verti
cal vibration at 190 cps. Camera framing rate is 16 frames-per-second.
The strobe may besynchronized to the camera and event by using
a photo-pickoff and a Type 1531-P2 Flash Delay Unit as described in
Section 5-3.1. This provides single-flash exposure of each frame when
the shutter is open, allows any phase of the subject cycle to be photo
graphed conveniently, and automatically adjusts flash rate to follow
speed variations of the subject (see Figure 6-4).
Remember that for
most shutters (which are open 50% of the time and which are properly
synchronized), the camera framing rate must not exceed 50% of the sub
ject frequency if adequate allowable flash delay is to be provided so
that all phases (360°) of the subject cycle can be examined (see Fig
ure 6-5).
Unlike still cameras, conventional movie cameras are not sup
plied with internal mechanical contacts or other synchronizing means.
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