If you are a fan of prime lenses and you’ve used wide-angle lenses before then you’re no stranger to converging lines. Look at the photograph above, notice how the left wall looks as though it’s leaning away from you and the entire building looks as though it’s bending backwards. This is not some miracle of architectural genius, it’s the result of shooting with a wide-angle lens not perfectly leveled with the horizon. When you angle your wide-angle lens above or below the horizon parallel lines will look as though they are converging. This happens slightly with all lenses but a wide-angle lens exaggerates it due to the lens capturing a wider expanse of the lines.
If you’d like to correct this you can either make sure to focus the camera completely parallel with the ground (don’t angle it up or down at all) or you can zoom in to narrow your angle of view (or switch to a telephoto lens if you’re using a prime lens).
Usually converging lines are avoided when photographing buildings but sometimes you can use your wide-angle lens and the ensuing converging lines to create dramatic and interesting photographs:
The first image above is the ever popular shot straight up between large trees to give the illusion the trees are enveloping the photographer. It’s an easy shot, just point your camera (with a wide-angle lens of course) straight above you when there are five or six trees around you and hit the shutter button. The second photograph is of a rather ominous building on a cloudy evening, taken with a telephoto lens it would have looked boring but with the wide-angle it looked as though it towered for miles above me.
As with anything, give it a try to see what you like. Wide angle lenses are often best used when they are capturing things in a creative way as opposed to just trying to fit as much into the frame as possible.