Interesting subjects make for great photographs, so are interesting backgrounds. Photographer Karl Zemlin has a great DIY for projecting strobe light to create interesting backgrounds. (He also has a nifty DIY section on his site)
What makes this design really rock is the little tripod socket at the bottom, so you can simply place this behind your subject on a light stand and have a symmetrical background.
1. start with a cardboard box about 10.5″ x 8.5″ x 7″. This size works well for the most strobes and for most Fresnel lenses. It is also small enough to remain pretty much hidden if carefully placed behind the subject.
2. To get a nice thrown background, you wanna have the glass placed at the focal length of the Fresnel lens. (yea, it is the same focal length from your camera lens). First you’ll need to measure it. Here is how you do it: Place the lens between a light source and the floor, and move it up and down until it gives you a sharp dot of light on the floor. The distance from the floor to the lens is your focal length.
You want this value to be small so it the lens to glass distance can fit in the box. You can stack a few of those to reduce the focal length.
In the case below, a stack of 3 Fresnel magnifier lenses had a combined focal length of about 4″. Glue foam-core guides in place to hold the glass samples near the focal plane of the lens
3. Cut foam-core windows that match the inner size of the box. Use hot-melt glue to secure the glass pieces to foam-core carriers
4. Now, to prepare the strobe housing. Craft foam around the opening for the flash helps prevent light from escaping. The ball bungee holds the flash in place. The wood block has a 1/4-20 T-Nut to help mounting this to a light stand.
5. As you can see, The ball bungee provide a strong grip for the strobe.
6. There are foam core flaps glued to the box flaps. The first foam-core flap goes to match the box flap and to provide some lift. The second foam-core flap goes on the second box flap and is a little extending a little bit. The last flap goes on top of the rift flap and extend all the way to the end of the second flap. Enter Binder, to close the box when using it.
Here are two tests shots taken using two different sheets of glass.
We would love to see portraits using this technique pop up on our Flickr pool.