Photos of lightning bolts. I use several techniques to capture lightning depending on the storm. If there is enough activity, frequent lightning, I will use shutter priority on a very fast setting in medium or the first large size jog setting and just fill the burst using my feel for the storm. If the lightning is sporadic I will use long exposure usually 10 to 15 seconds on apreture priority. Again depending on the activity, I will use RAW if the lightning isn't too active or JPG if there is a good amount of lightning.
Like all special or creative forms of photography there is no one correct way to achieve the shot, a lot of practice is really the only thing that will help you along. When it comes to weather, each storm is different and even each location you try to capture lightning in will affect the method you use to try to capture it.