I love chasing storms - to the extent that I've stayed out till past midnight driving around the high desert chasing lightning storms that I know will start fires I'll be flying on the next day...
I've used everything from 10mm to 200mm, and it would be hard to pick a single focal length range for this sort of fun. In tight quarters, a wide (say 16mm) to normal lens works best, though you'll question whether you should be outside in such conditions
. In wide open country, I prefer a telephoto lens since I can stay outside the rain and gust front winds while still getting close to the action. Personally I found 10mm Fisheye to be too wide, as the lightning is a small feature of the photo, though this could work amazingly well if you were really immersed in the storm
.
Having a hook or some other means of weighting your tripod is important in these conditions as the winds can be sudden and intense (I don't want to talk about how I learned this lesson
).
I've had the most success at night as have most folks I've seen, though I've got a few nice shots at dusk too. The nice thing about night is that exposure length doesn't matter - it's dark... in fact aside from noise and DFS (dark frame subtraction) issues, the easiest exposure length is to lock the shutter open in Bulb mode and wait for lightning to occur within the frame - this worked very well on my CCD based K200D with exposures up to a minute or so, but with the K20D and the K-7, the forced DFS leads to lost shooting opportunities, and it always seems that the best strikes occur while your camera is doing it's DFS/NR mojo, so with these cameras I've been employing a strategy of shooting a continuous series of exposures, each one short enough to not trigger DFS. This works pretty well, but leads to
lots of throwaway shots. As for sensitivity and aperture, I've found that ISO 400 and f/3.5 is my baseline setting, and I adjust from there.
Regarding WR lenses - they're great piece of mind for this type of shooting on a WR body, but I find that since you're pointing the lens up toward the clouds, you tend to get a lot of water drops on your front element / filter, so I haven't actually shot much lightning while it was actually raining on me (though I have hiked a mile back to town at midnight through a heavy downpour
). I would worry more about a waterproof case / bag / cover more than the lens itself.
Here's a few of my best lightning shots to date...
24mm, ISO 400, f/3.2, 45 sec. (bulb mode)
200mm, ISO 100, f/5, 10 sec. (at sunset, so not fully dark yet) - cropped for zoom and composition
43mm, ISO 400, f/4, 2 sec. (using a polarizing filter to darken the scene to get longer exposures while shooting on continous)
115mm, ISO 400, f/3.5, 20 sec.