How to shoot lightning?
Weather Studios Shooting SecretsA useful tool for shooting lightning during daylight hours is a neutral density filter. This will allow you to reduce the amount of light entering the camera without introducing any other optical affects. As such, they are used to get longer exposures, which greatly improves your chances of catching a strike while the shutter is open.
At night, focusing and exposing successfully on a strike that is yet to happen will always be challenging and can result in many out-of-focus shots. Set the focus to infinity and use a smaller aperture to increase the depth of field. As soon as you capture a strike, however small, preview the image to ensure that the focus is good, so that when the bigger strike happens you can be confident that it will be in focus.