I realized I hadn't been out with the "big" flash after dark for awhile, and it was such a nice clear night I thought I'd harness up the HapDog and go have a lurk around.
I played around with some conventional long exposures, then got stuck on my camera's "Night Mode" (nothing to do with a Bob Seger song).
Night mode is where the flash goes off, then the camera keeps the shutter open as along as the meter thinks it should. I think it reads a little fall-off of the light from the flash so things don't get too over-exposed. You can set the camera to flash "front-curtain" (before the long exposure) or "rear curtain" (after the long exposure) or both. The result is you get some amount of front-lighting with a nice saturated image from the long-exposure. If the backlighting is just right it starts balancing out the flash.
These pics are all front-curtain sync, but I found I needed to play with my flash output a little. Sometimes I bracketed from -1 stop to zero, I don't think I had to go + on anything. The long shutter time depends on where you point the camera's meter too, so there are a few things you can play with.
When you have other types of light sneaking into the long exposure, it's hard to predict what you'll get. That's why I like it. I didn't PhotoShop these other than cropping and maybe a smidge of contrast and saturation adjustment.
The white spots in the foreground are a mix of spray and gnats. You don't even see them without the flash on. Nice ribbony water.