The Dolly Zoom is a strange, great filmmaking technique that has the power to make or break an emotionally charged shot. It's other nickname, the Vertigo Effect, comes from the fact that the dolly zoom was first implemented in Alfred Hitchcock's 1958 film Vertigo. The technique, which involves zooming in while you physically move the camera backwards, creates a distorted, uncomfortable sensation where the foreground feels like it's moving forward while the background gets sucked quickly back. 

As effective of a shot the dolly zoom can be, it's not always the right choice to make. Filmmaker Bhushan Mahadani explains:

"The Dolly Zoom is only effective (and curiously invisible) when it visually amplifies the internal emotional mindset of a character’s critical story moment."

The first use of the dolly zoom, trying to visually reproduce the sensation of height-induced vertigo.

To learn more about the science behind how the dolly zoom achieves that mind-altering effect, you can read about it at Filmmaker IQ's mini-lesson on the introduction to the dolly zoom. It's one of those techniques that is so fickle and prone to being too hammy (think the dramatic zoom) that a lot of thought has to go into to whether it would help or hurt the scene in which it's being used. But when it works, it works, and it's worth exploring for independent filmmakers looking to add something new to their repertoire.