Photographing lightning can be exhilarating, particularly if you happen to be in the middle of the storm. Although I don’t make a habit of chasing storms, I have been caught in a few, and made some photos in the process.
Above all else, my first bit of advice is to be safe as you photograph lightning. Don’t be too exposed in the open, and if possible, get into the safety of a car and remotely operate the camera.
As for the exposure settings, this can really depend on the environment you are making photos in.
If you are photographing lightning during the day, then you really just need to expose for the daylight conditions and hope that you can press the release at the moment you see lightning. Believe it or not, with some of the longer ground strikes that we see in Australia, it is actually possible to photograph lightning with a smartphone.
As for photographing lightning at night, the usual technique is to set the camera up on a tripod and leave the shutter open for long exposures. There are some interesting factors that come into play though. If you are making photos in the city, then the exposure is going to have to be moderately short, simply because the city lights are bright. In the country, and with no full moon you can leave the shutter open for a lot longer.
So, where to start at night. My advice would be to set the camera to a lower ISO (400 ISO is a good starting point on most cameras), set the aperture to about f5.6 and then start testing what the best shutter speed is for the occasion. If you are in the city, you will probably be on shorter shutter speeds of about 1-seconds to 8-seconds (not to be confused with 1-second to 1/8th of a second). Make a test photo; if it is too bright, shorten the shutter speed, and if it is too dark use longer shutter speeds.
Once you have determined the shutter speed, just keeping making exposures with the plan being to capture a great photo of the lightning.
Now for the fun part; lightning is no different to ordinary flash photography. “What does this mean” I hear you ask? It means that while the ambient (constant) light on the scene can be controlled using shutter speed, how bright we make the lightning appear is controlled by adjusting the aperture. If the lightning appears too bright, close down the aperture; if it looks too dark, open the aperture.
As most photographers discover as they start taking control of their exposures, the ISO, the shutter speed and the aperture all control how much light get into the camera. Our job is to discover how to apply them to every situation!
All the best, and keep safe!