|7s, f/11, ISO 100, 17mm, fluorescent
First, be safe. Don't stand there next to your tripod in the middle of an open field during an electrical storm. You don't want to be the tallest thing around. Nor do you want to stand really close to the tallest thing around (like a tree or a lamppost), because the electrical charge can radiate through the ground out from the base of that lightning rod for many feet. The perfect spot from which to shoot is many miles away from the storm, where you're safe and dry. If the storm is closer, go inside and shoot through a window. An openable window is best, but a clean, dry sheet of glass (no screen) will do in a pinch.
Now that you're guaranteed to return home safely so you can view these great photos, let's start shooting.
|10s, f/8, ISO 100, 200mm, tungsten
There isn't a great deal of equipment required for photographing lightning. You really just need a camera (duh), lens, tripod, and cable release or remote trigger.
Just about any tripod will do, although the windier it is, the sturdier and heavier your tripod should be in order to keep your camera stationary throughout the entire exposure. Don't try to rest your camera on a car window or stand your tripod on your hood if there's much wind, or if there are other people inside the car. Your vehicle's suspension is soft enough that even a slight wind or interior movement will wobble the car around, rendering a great shot unusably blurry. If you're the only one in the car on a calm night, you can probably get away with it. You can get camera mounts that clamp onto the edge of a partially open car window, providing a very portable mount for these situations.
|11s, f/8, ISO 100, 100mm, tungsten
I don't care how fast you think your trigger finger is -- you can't reliably wait for a bolt to appear before you hit the shutter button. The best method is to simply take one long exposure after another in hopes that you'll catch one or more bolts in your frame. A really active storm can provide multiple bolts in a single frame for a really stunning composition. In a slow storm, you'll end up with lots of throw away shots of a dark sky, but that's the price of admission. For a dark, night sky, I usually use between 7-15 seconds with good results, though this can leave fast-moving clouds rather blurry, so you might need to shorten the exposure in high winds. More later on exposure settings.
|7s, f/5.6, ISO 400, 21mm, tungsten
Because you generally want the background of your lightning photos to be quite dark, you shouldn't rely on the camera's automatic exposure settings. Instead, do everything in manual mode. Setting the correct exposure for lightning is not unlike exposing for flash photography. To your camera, there are three components that affect the amount of light your camera records: ISO, aperture, and shutter speed. Because a lightning burst is so brief, the shutter speed doesn't have any affect on how brightly the bolt is recorded. Consequently, you need only to set your ISO and aperture to a good value for imprinting the lightning. For typical bolts, I find that ISO 100 + f/8, or ISO 200 + f/11, make a good combination. Darker settings will make fainter bolts really blend in with the background, which isn't what you want. With the ISO and aperture set properly for the lightning bolts, you can adjust the shutter speed to get a good exposure with minimal motion blur on any surrounding terrain, including clouds.
|10s, f/5.6, ISO 200, 17mm, fluorescent
Speaking of focus, autofocus can be hard, and your camera certainly can't focus on a lightning bolt quickly enough to make the shot. You need to pre-focus on something else ahead of time -- like a distant building or the horizon -- and then set the lens to manual focus (MF) so that it won't try to refocus on an empty sky before every shot. Don't just blindly turn your lens' focus ring to infinity, as most lenses actually allow you to turn the ring past infinity, resulting in a blurry shot.
|16s, f/8, ISO 100, 135mm, fluorescent
The final thing I want to discuss is composition. Sure, lightning by itself in an empty sky can be impressive, but without some sense of scale, it's impossible for the viewer to really understand how big the bolt was. Consequently, I always try to include some frame of reference in my lightning shots. It may be the horizon line with a few trees or a cityscape. If the cloud-to-cloud lightning is mostly overhead, sometimes the only other features I'm able to include are some cloud formations. Take a couple no-lightning test shots of the surrounding terrain to make sure your shutter speed is set right to make the terrain look good.
|13s, f/8, ISO 100, 70mm, tungsten
I throw away lots of empty or lackluster shots, but you just have to expect that. The title photo at the top of this post was the only shot out of 137 that night that caught any lightning at all. Every other bolt was either out of frame or between frames. I'm glad I didn't get discouraged and quit early.
Got any tips of your own to share? Speak up in the comment section below!