Have you ever wondered what ‘Rear Curtain’ or ‘Rear Sync’ means in your flash menu? All DSLRs and some compacts have this option. To put it simply, rear curtain flash enables your flash to fire at the end of the exposure time, as opposed to firing as soon as the shutter opens. In most cases, this wouldn’t really make a difference, and that is probably why this feature so often goes unnoticed. When you are synchronizing your flash with slow shutter speeds… it makes a world of a difference! Take a look at the image above (photographer Kent Simpson)
One of the most common subjects people shoot to practice rear sync, is moving cars. You could try with a model car to see how effective rear sync can be. The first step would be to get an ambient light exposure reading using a shutter speed of 1 or 2 seconds. Next, turn the rear curtain feature on, and pop your flash open. Then, get a moving subject to practice with and fire the shutter capturing motion blur followed by a nice sharp image of the subject…
Here’s a good example of what a model car can look like when photographed with a motion blur and a rear sync flash.
