I love the way so many of your gorgeous photos have a point of focus in the foreground and then artful, colourful blurriness in the background. Particularly when there are little flares of light and it looks like something made of Philip Pullman's Dust. Any pointers on how to do that? Whenever anything like that happens to me (with my trusty point and shoot) it is a happy fluke. ~ Christine (spiral bound)
The moment I realized how profoundly fulfilling it was to control depth-of-field, I grew out of my point-and-shoot camera. You may find the same thing, hit your head on the same limited ceiling as I did. That said, there are ways to capitalize on what you have.
Aperture, which controls depth-of-field, is expressed in f-stops. The lower the number (f2.8, for instance), the blurrier the blur. This works well for portraits and nature. The greater the number (say, f11), the deeper your range of focus, which is suitable for landscapes or architectural shots.
Some point-and-shoot cameras have limited semi-manual modes -- my old one did. It wasn't nearly as effective as what I can achieve with my SLR, but it's playable. First, check your manual to see if your camera gives you the option of shooting in aperture priority mode. Some do -- this might show up as 'A' on your mode selector. If your camera doesn't offer this, try shooting relatively close to your subject in 'portrait' mode. It's not as accurate as controlling true aperture, but in portrait mode, your camera will automatically set itself to an f-stop that will blur the background somewhat.
If you have an SLR camera, start experimenting by switching to AV or aperture priority mode. This is a semi-manual mode that tells the camera to keep your exposure steady by compensating with shutter speed as you change the f-stop. This is a great way to get a better understanding of depth-of-field without overwhelming you with too many other variables if you're not accustomed to fully-manual shooting.
Now let's talk about the fun stuff.
Christine asked about Philip Pullman's Dust. She's talking about what's called bokeh, an effect that makes everybody go all drooly and gushy. Seeking out bokeh-rich conditions and setting your camera to exploit them is an addictive pursuit.
Bokeh is what happens when points of light in the distance are abstracted by a wide-open aperture (an f-stop with a smaller number). I went out to find some yesterday, and ended up sitting on the ground, shooting up into the giant spruce in front of our house. I didn't have high hopes when I stepped outside -- it was an overcast day with the flattest of light. I may as well have been shooting in a Wal-Mart. But if you're hungry for bokeh, a tree will oblige you even on the dreariest of days.
In aperture priority mode, I set my camera to f 3.2 at 400 ISO. With the yarn about three feet away, I used my 50mm f1.8 lens, which is fancy-talk for The Sweetest Little Canon Glass You Can Buy When All You Have Is 150 Bucks.
To capture bokeh, look for a subject that has dappled light or points of light behind it, usually caused by brush, foliage, trees, or distant electric sources. The closer the dappled light, the more intense your bokeh will be. In the first shot, the broken light in the distance made for subtle bokeh in contrast to the second shot, which was immediately surrounded by a tangle of limbs and branches. Once you're situated, take several frames across a range of blurriness, from almost totally abstract (f1.8) to a blur with greater contrast and definition (f5.6). Different apertures will change the shape of the bokeh, and this is how you'll learn what you like.
Bokeh is an active participant in an image. Take an active role in shaping it. Consider background composition with the same reverence as you'd consider for the foreground. This may all sound finicky, but it's not. There's nowhere near as much mystery to bokeh as you might think. It's pure joy, finding that sweet spot.