I’m beginning to take slideshow production more seriously, not least because it’s a key part of my next book, which I’m still writing. One of the interesting, tempting, but ultimately risky techniques is injecting movement into still images. The standard technique for this is pan-and-zoom. In this, the view starts with one framing of a photograph and ends with a different framing. The effect replicates what would happen in a video if you operated the zoom and/or panned the camera during filming. It was originally developed for television and film as a way of bringing life to rostrum camera copy shots of prints and paintings, and is also called after the names of two people who specialized in this — the Ken Burns effect in the United States as, and the Ken Morse effect in Britain. Done smoothly and with some thought for the start and finish positions (as with any camera movement), it can draw the viewer into the scene and also direct attention. But it also tempts over-use.
As the name has it, there are two separate directions, which can be combined or not as you like. Panning is across the image, in any direction, and zooming is a change of scale, either in or out. The variables are the extent of these movements, and the time taken. A succession of pan-and-zooms, one after another on different images, can become dizzying and irritating, and even if you like the effect in principle, it’s as well to moderate it. But there’s an exception, and this is using repetition to build up an expectation. As long as the movements blend slowly into each other, a succession can go on for quite a long time comfortably. Here’s an example, but the devil is in the detail. To keep it flowing smoothly, and give the sense that the viewer is floating forward through everything, the pacing has to be consistent, as do the dissolves, as does the range of the zooms. And possibly most important of all, they need to be centered, exactly. Beyond that, it’s an interesting exercise in choosing sequence, progressing from one subject to another, varying similarities and contrasts, and playing with the graphic effect that only a linear show can produce — the match dissolve.