Digital Photography Hacks

Second-Curtain Flash for Cool Effects

One of the most magical of all camera tricks, second-curtain flash lets you show a trail of motion behind an object that is frozen in mid flight.

Typically, you use a camera flash to add light when there’s not enough ambient illumination for a well-exposed shot, or to fill in shadows for portrait subjects. In either of these scenarios, you typically have a relatively fast shutter speed (1/60 of a second or so) with the flash occurring at the beginning of the exposure, otherwise known as the first curtain. The term curtain refers to the phases of the shutter. The first curtain occurs at the beginning of the exposure and the second curtain occurs at the end.

For an evening portrait, you use a much longer exposure time [Hack #29] to capture some background information that would otherwise be dark because the flash can’t reach that far. Subjects must stand still during these long exposures; otherwise, they’ll blur in the photo.

Technically, a second-curtain flash is just a technique in which the flash fires at the end of a long exposure rather than at the beginning of it. So, why would you ever want to have the flash fire at the end of the exposure? Well, it creates great opportunity for the best of both worlds. On one hand, you get the artistic motion trail that illustrates the movement of an object, often revealing patterns or characteristics about the movement that we can’t otherwise perceive. On the other hand, you also get to freeze the subject ...