Slow / Rear Curtain Sync Flash Technique

[dnpayne]

So, I've been seeing a lot of photos lately by wedding photographers who utilize the slow sync flash feature for reception photos. I've been trying to mess with this a little with no luck. I'm looking for some tips on the technique used to capture these types of shots.

I have my camera on rear curtain flash. What other settings should I be paying attention to and what technique is used to achieve these? Im guesing you have to move the camera a certain way as well?

See example attachment.

[ErikUngerPhotography]

The movement of the camera is just following the movement of the action. Move (pan) with your subject. You will use a slower shutter speed, hence the motion of the lights in the background. Of course the flash freezes your subjects. Though what exact shutter speed depends on other settings as well and power of your flash.

[zona5101]

so are the wedding images you're seeing reflecting the dark backgrund and light trails like in the image you posted??? Or are they using the rear curtain sync to drag the shutter to increase ambient exposure with flash at the end???

[Doug Sundseth]

When the scene involves both motion and a dragged shutter, you'll get motion blur that is stronger farther from the flash and less significant close to the flash. Rear-curtain sync is useful in that sort of photo, but the phrase refers only to when during the exposure the flash fires. For a photo with motion, this means that any blurred part of the photo will be behind rather than in front of the subjects.

I think what you're talking about here is "dragging the shutter": using a slowish shutter speed to add an ambient component to an otherwise flash-lit scene. So long as you're below your camera's flash sync speed (generally 1/160 - 1/320 second, though there are exceptions), shutter speed has no effect on the flash contribution to lighting, so you can use shutter speed to independently adjust the ambient contribution.