Unusual weather conditions can help create dramatic scenes. In this image the lightning, moody clouds and the warm glow in the distance help keep the viewer's interest. The leading lines from the tracks into the storm also help.
We spent a few hours chasing this storm through various communities, hoping for a decent shot. We got lucky finding the lighting and the tracks just about an hour before the sun set and the storm diminished. The day paid off as this image ended up in the 2011 Calendar of CBC's the Nature of Things with David Suzuki :)
Now the more interesting details...How did I take this?
Lightning can be pretty tricky to shoot by trying to time it. Most are just too quick for the finger to trigger quickly enough (some strikes spread slowly over the whole sky and are doable). So the trick is the use long exposure (for evidence, check the clouds for movement). In this particular case I used 30 seconds at ISO 200 (base for D300) and f-6.
Since this shot was taken before the sun set - although cloudy - there was still plenty of light. The above settings on their own would have over exposed the entire scene. To compensate for this, I used a 12 stop Neutral Density (ND) filter (about $130 for a 77mm size). A neutral density filter is just a darkened filter that does not alter anything except the amount of light passing through it. This particular filter is so dark that you cannot view much through it. This leads to some issues. If you simply put this on your lens with autofocus and metering to anything other than manual, you will not succeed. IT's simply too dark for the autofocus or metering to work effectively. Here's what I do:
1) Manual or autofocus on the subject without the filter.
2) Turn off autofocus
3) Manually meter the scene (First decide on f-stop the adjust shutter speed until you get the exposure right)
4) Take a shot and make sure you get the result you want (not over-exposed or under-exposed)
5) Put the filter on
6) Adjust the shutter speed to compensate for the ND filter (example: metering before filter indicated 1/200sec -> final shutter speed should be 1/25sec. If you are confused about this please see previous blog: f-stop-iso-and-shutter-speed)
7) Take the shot!
Don't forget to use a tripod and remote trigger (wireless or cable). If you don't have a trigger, use timer. Although I used the 12-stop filter, this could have been accomplished with a 3 or 6 stop filter and bumping up the f-stop (some softness may occur if you go too high). In the end, if you have to choose only 1 ND filter a 3 or 6 stop is more versatile in your bag than a 12-stop.
Remember not to step on tracks if near lightning, even though as in this case, the lightning is a mile or so away.