Thursday, November 11, 2010

Rear Curtain Flash!

Some cameras offer the ability to fire the flash at just before the second curtain closes. This is called rear (or second) curtain sync, and it is used to freeze motion at the end of the exposure. When making long exposures while firing a flash, rear curtain sync creates the effect of motion blur trailing the main subject.
In this photograph, the image is again lit by two sources, the ambient light of the club and the light of the flash. The difference is that in this photo, the flash was fired at the end of the exposure. Using 2nd (or rear) curtain sync this way causes the motion blur of your subject to appear behind the sharp area of the subject in the photograph and enhances the effect of the motion.

To sum it all up: front curtain = BAD rear curtain = GOOD. Ok, ok, that’s pushing it a bit, I know. I’ll say it this way: - Front Curtain flash = having a sharp subject then smugged over it by movement blur
- Rear Curtain flash = having blurry movement then with a sharp subject over it


  1. Awesome explanation, thank you! Q: is 2nd curtain sync an advanced feature found only on spiffy expensive DSLRs? Or is it a fairly common feature?

  2. i guess its a pretty pro feature but these days smaller cameras can do everything and I'm sure it can be found on some point and shoots as well.