I have been taking photographs since I was about 12 when my folks bought me a roll-film Kodak Box Brownie; back when you couldn't buy colour film because it was too expensive. In all this time I have never really bothered to try taking pictures of lightning. Along the way I have belonged to various camera clubs, done various 'hobby' photography courses, and read thousands of photography articles so I knew the basic theory; (a) use a tripod, (b) select a relatively small/slow aperture (somewhere around f16 to f22 depending on the lens being used), and (c) set a long exposure of around 30 seconds up to two or three minutes depending on the frequency of the lightning flashes.
Tonight we had an electrical storm go over Kalamunda so just for the fun of it I set my camera up in the back yard. The lightning flashes were frequent so I selected a 30 second exposure, an aperture of f16, and set my trusty 18-135 lens at full wide-angle (18mm). I got to take five frames before the rain got too heavy to leave the camera out in it, even though the Pentax K-3 is certified 'weather proof'—I just didn't want to take the chance.
This is the best of what I got.
Click on the picture to see it at 1,733 x 1,000 pixels (assuming your screen can display a picture of that size).
I realise now that I should have turned the veranda house lights off and I am not sure why the sky (which is actually the bottom of the storm clouds) has a purple tinge. I can only assume it is a white balance issue with the camera and the kelvin rating of lightning—yet the other colours in the picture look correct (the house roof and veranda posts).
I'm not sure I will ever bother taking other lightning pictures so this could well be the first and only attempt.