How Did They Do That?!? The Dolly Zoom.
Dec 20th, 2007 by Leo Geis
I’ve been asked by a couple of people lately about a cinematic technique that is evidently still in demand: The Dolly Zoom (or “Zolly”). The camera position is apparently static while the background zooms either toward or away from the viewer. OK…it’s pretty cool, but it’s old and busted (I think that means “cliche’”), and there are much more sophisticated (and expensive) alternatives.
A Dolly Zoom actually involves either moving the camera away from or toward the subject while zooming to keep the subject at a constant size on the film plane or sensor. Because you have already read my post on “telephoto compression” you fully understand how subtended angles affect the perception of the viewer and would produce a remarkable effect in a dynamic application.
The only reason I’m including this technique on my technical photography blog is that I’m considering using it in an upcoming time lapse gig. The motion control will obviously be critical, and we’re considering ways of precisely incrementing the dolly’s position. It’s interesting to consider, too, the potential for a Zolly slit-scan image, or a Zolly slit-scan time lapse-but that’s really getting wrapped around the axle-the tedium would require a well coordinated team to produce each frame.
There is an alternative method I’ve figured out, but it would involve simply running frames, then automating (in Photoshop) a virtual slit-scan process by using horizontal or vertical slices of sequential images. The number of images would be staggering, and while the Histogram statistics are easily controlled to alleviate time-lapse flicker, the motion control synchronization would be extremely demanding.
Concerning alternatives for the classic Zolly, there is an extremely sophisticated technique for distinguishing the subject, context, and chronology called “Bullet Time” or “Flow-Mo,” which involves high speed cameras on computer-motion-controlled dollys and/or a series of still cameras placed in formation around a subject. At present, the the technique is reserved for feature films and high budget commercials, hinting at the cost, computing, and expertise necessary for such a product. Read more about “Bullet Time” here.
L