Rear-curtain sync

…In the last movie, you saw how we could combine…a slow shutter speed with a flash to get an…exposure that a well exposed foreground thanks to the flash…and a well exposed background thanks to the long shutter speed.…Now, the thing about a long shutter speed that you're probably already used…to is that a long shutter speed allows you to create motion blur.…So, is there a way that I can use that motion blur in an image?…A, a low light image with a flash to…create any kind of effect.…Obviously I wouldn't be asking that question if there wasn't.…Have you ever seen an image that looked like this.…

I've got this wonderful streak behind my subject, but the subject is frozen.…That streak is coming from a slow shutter speed.…The frozen image is coming from the flash, so this is a slow sink image.…The trick to it is I need to control when the flash is firing.…If it fires at the beginning of the image, then they…are a still image with a blur on top of them.…If I fire them at the end, then I get a blur with them at the end.…