Christmas lights can be a lot of fun as a photographer...
One of my favorite things to do is to make them fuzzy little highlights in the foreground or background of a photo. All of these photos involve Christmas lights hung on the side balconies of Terrell ISD's Performing Arts Center.
Opening up to maximum aperture (in this case, f2.8), will do the trick, especially if the lights are a good distance from the subject. Using longer telephotos make the background look closer, and the out-of-focus effect will be great, like this one from backstage, behind the elves. (just wish I could get some smiling parents in there too... could not find the angle.)
Canon 40D, 120mm at f2.8, 1/125, iso800
For a really cool effect, put the lights between yourself and your subject. Up on the balconies, you might think that the lights are in the way...
Canon 40D, 115mm at f2.8, 1/200, iso80
... But if you focus through the lights to your subject, the lights turn in to little dots of translucent light over your subject.
Canon 40D, 115mm at f2.8, 1/200, iso800
With some careful composition, you can find a point of interest and frame it with the lights. We cropped this one down a bit for the newspaper, but the group of musicians in the center becomes the focal point when the rest are obstructed by dots.
Canon 40D, 200mm at f2.8, 1/160, iso800
You can also use lights on a tree to frame one side of a photo with lights... this one with colorful lights was on the far edge of the stage.
Canon 40D, 200mm at f2.8, 1/125, iso800
To make it a really cool photo, you also have to catch a great moment, which didn't happen with the shots above.... my favorite shot from the TISD Christmas programs was during a choir concert... alas, no lights. Poor girl almost got slapped in the face.
Canon 5D, 200mm at f2.8, 1/200, iso 1000
Have fun playing with the lights....
don j.