Rear Curtain Sync.

With streaks going in the right direction, this article examines how to capture streaky headlight shots.

By combining flash with a long exposure you can achieve some great shots. You can get ghostly movement blur and trails of light from moving light sources if you subject is sharply lit; usually all you need to do is set your camera to slow sync mode and start shooting.

The shutter stays open to record the ambient light and movement blur when in regular slow sync mode since the flash fires at the start of the exposure, but this can be problematic. The effect may look wrong because the blur is traveling ahead of your subject instead of behind it if your subject is clearly heading in a specific direction, for example.

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A “pop and burn”, where the flash fires at the end of the exposure, so that the movement trail is behind your subject, is an additional feature of most cameras called a rear curtain sync flash mode (or, second curtain sync).

But slow sync flash isn’t the default mode; when the flash is at the end of the exposure it’s very difficult to time your shots. But, when these types of shots work they look terrific, so it’s worth the effort.

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Front Curtain Sync vs. Rear Curtain Sync.

The difference between front curtain sync and rear curtain sync are shown in the two shots above. The light trails that are in front of the bike are the effect of front curtain sync because the flash is fired at the start, or front, of the exposure. The light trails that are behind the bike are the effect of rear curtain sync because the flash us at the end, or rear, of the exposure.

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1. Set Up Your Shot.

Carefully plan your composition. You need to frame the shot to allow room behind for the light trail so place your subject in the position you want it to be in when the flash fires with this in mind. The camera won’t track a moving subject in the dark so now is a good time to set the focus.

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2. Switch to Manual.

You want a long enough exposure to record the light trail but you still want some of the ambient background light to register from the main light that will come from the flash. Try a one-second exposure at f/5.6 and avoid smaller lens apertures so as not to sap the flash power.

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3. Manual Flash Power.

It’s simpler to experiment with the flash power manually in situations like this as opposed to using TTL auto flash. Choose the power setting when you have switched your flash to manual mode; 1/1 is full power, 1/2 is half power, etc. Outdoor shots will require plenty of power.

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4. Rear Curtain Sync.

Now change your camera’s flash mode to rear curtain sync or second curtain sync. Some models of camera require hot-shoe add-on to enable the function so check your camera for what method you need to employ to achieve this.

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5. Try Some Shots.

Positioning and timing need to be right so you’ll need a willing subject who’s prepared to drive up and down while you get set. It can take some practice to time the shot so that your subject is in position at the end of the exposure and not the start.

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6. Final Directions.

You’ll need to give your subject precise instructions in order to get proper control over the timing and length of the light trail. For example, the bike in the shots is only traveling at 12mph even though the shots look fast! To help with focusing get your subject to follow a fixed line through the shot as you experiment with rear curtain sync…

Words by Elijah (Content Marketer) via Digital Camera World.