With Christmas lights aplenty, it's a great time of year to try your hand at some shaped bokeh shots. Here's a basic how-to guide to get started.
1- Drill your hole in the center of the cap.
2- Sand both sides of the hole.
3- Cut a small foam/paper square for the inside of the cap.
4- Cut out the shape in the center of the foam/paper. (Test the size you want
to use by punching a shape on a 3x3 square piece of paper and hold over your
lens, smaller shapes work better.)
5-Tape or glue the square onto the lens cap.
Note: There's another method to making a shaped bokeh mask which is done by creating a paper hood for your lens. Both methods work fine, but the cap construction described will hold up better over time. The possibility of shapes are also endless- stars, hearts, letters, custom shapes, etc. Be creative and have fun with this!
Any lens that has an aperture of F 2.8 or larger (preferably F 1.8 or even larger, the bigger the better for this).
Shoot with a wide open aperture (or lowest aperture number), and on manual focus.
To achieve the best results: Shoot the photo's at night time or in the dark. You can shoot different types of lights, but Christmas lights work best. To get the shapes to appear you must take the photo out-of-focus (don't focus on your lighted subject, but focus the shapes in the lights). The smaller the light source is, the closer to the subject you'll need to be. Experiment!