I love to photograph and thereby capture lightning but this can be a dangerous hobby and/or profession as an extreme weather photographer. A lightning storm is unpredictable and therefore dangerous so you must be fully prepared and educated about this wild subject.
Capturing lightning or any other kind of extreme weather is also challenging and rewarding!
Here below are some tips and techniques:
1) Safety first! Find a good cover -- staying inside a building, a car or any other object that can protect you from a direct impact is the best. DO NOT photograph from an OPEN AREA especially if there is water, tall trees or structures nearby. Stand at least 50 feet away from water and tall trees/buildings.
2) Prepare your equipment -- a DSLR with a tripod and remote shutter release is a must! Long shutter speeds between 3 and 30 seconds are mainly used if you are shooting without a lightning trigger. A tripod is a must to prevent shake at these long shutter speeds otherwise you will get blurry images. Long exposures will work better for night-time lightning since the sky is already dark. Long exposures used for daytime lightning will possibly over expose your images and so a multi-stop neutral density filter may be used or a lighting trigger. Wide-angle to normal prime lenses work best and so do wide-angle to mid-telephoto zooms. This allows the photographer to compose for a wide area of the sky. Set your aperture to around f5.6 and check your exposure. Made adjustments as necessary. Be sure to establish an earth and sky connection with a landscape.
3) Use instant radar apps on your cell phone or tablet to watch potential thunderstorms develop. Thunderstorms that reach "severe" levels are the best to chase and photograph since they will have the more photogenic and also more lethal "cloud-to-ground" lightning. "Super Cell" thunderstorms are the deadliest and are the ones that most produce tornadoes. Use the radar apps to see forecasts, intensity of the storm, direction so that you can plan to either wait for the storm to approach your area or you may need to "chase" the storm.
4) Be observant of hail, straight-line winds, micro bursts and the possibility of tornadoes! Today's apps give you all kinds of data.
5) Use a special camera cover or make one yourself to keep your camera as dry as possible from the rain. A large zip lock bag may work. You would need to cut a hole for the front lens.
6) Set your camera to manual focus and focus to "infinity". Do a test shot to look for image sharpness and exposure. You would need to manually focus your camera. Night-time lightning makes this much tougher so be sure to manually focus using the LCD screen while there is still some light in the landscape.
7) Set ISO to your lowest value - usually 100 for the best resolution, less digital noise and more colors.
8) Set your camera to full manual mode so that you will have total creative control of aperture and shutter. Where you set your aperture and shutter will depend on, first, what time of the day you are capturing lightning -- day or night? For daytime lightning, a specialized "lighting trigger" is the best!
9) A standard rule is to compose for 60-80% of the sky and 20-40% of the foreground.
10) Be patient and take many shots if you are not using a "lightning trigger" and above all, SAFETY FIRST!!!