A few months ago I ran across an article by Mark Gee, an astrophotographer from New Zealand, about how he made a series of night portraits using the Milky Way as a background (http://theartofnight.com/2014/03/under-the-milky-way-girls-by-starlight). The images he shared were stunning examples of the creative use of light. I decided to give it a try myself just to see if I could pull off something reasonably close to what he accomplished.
The hard part was finding a model who was willing to be up late in the evening. The most logical model was my wife Kris, but she tends to be a bit reluctant to do such things, so instead I was able to talk my son into helping.
Our original destination was the old barn located about three miles down the road. The location offers a good view of the southern and eastern sky and even with a sliver of the moon being visible at our appointed hour, it presence hovering above the horizon in the west had little impact on what I was trying to accomplish, but, we settled on the backyard out of convenience.
I set the camera on a small tripod I had built from spare parts that allowed the camera to sit about ten or twelve inches off the ground. Using an 18mm lens, I angled the camera just enough to gather in the sky and still capture him as he stood a few yards away. I manually focused on him using a light from his cell phone.
The technique was simple; he had to stand perfectly still for about 20 seconds while the camera made its exposure, then at the very end of the exposure process, I fired off my speedlight to illuminate him with a quick blast of light against the Milky Way backdrop. I purposely underexposed the image knowing that I would eventually boost it in Photoshop to bring out the dynamic light of the Milky Way, and I did not want to overcook the exposure on him.
The results were encouraging but the technique still requires some practice and a darker, brighter night to enhance the milky way. Regardless, it was a fun attempt at doing something different against the incredible diverse light of the night sky.