Few things in nature are more dramatic than lightning. Or more dangerous. And if “safety first” is a criterion for intelligence, photographers are stupid. Because lightning is both dangerous and unpredictable, the more you understand lightning, how to anticipate it and stay safe in its presence, the greater your odds of surviving to take more pictures.
The shocking truth about lightning
A lightning bolt is the atmospheric manifestation of the truism that opposites attract. In nature, we get a spark when two oppositely charged objects come in close proximity. For example, when you get shocked touching a doorknob, on a very small scale, you’ve been struck by lightning.
The primary process at work in an electrical storm is convection, the circular, up/down flow that happens when heat is applied to a fluid. As air warms, it becomes less dense and rises. The rising air cools with altitude and becomes more dense, causing it to sink. But the sinking air warms as it loses altitude, eventually rising again, and the cycle continues…. (Convection is also the process behind the bubbling of boiling water.)
Convection’s up/down flow creates turbulence knocks together airborne molecules, striping their (negatively charged) electrons. Lighter, positively charged molecules are carried upward in the convection’s updrafts, while the heavier negatively charged molecules remain near the bottom of the cloud. Soon the cloud is electrically polarized, more positively charged at the top than it is at the base.
Extreme polarity can also happen when a negatively charged cloud base hovers above the positively charged ground. Either way, nature resist this charge disparity and tries to resolve it as fast as possible: a lightning bolt.
Nature always finds the easiest path. If the easiest path to electrical equilibrium is between the cloud top and bottom, we get intracloud lightning; if it’s between two different clouds, we get intercloud lightning. A cloud-to-ground strike occurs when the easiest path to equilibrium is between the cloud and ground.
With lightning comes thunder, the sound of air expanding explosively when heated by a 50,000 degree jolt of electricity. The visual component of the lightning bolt that caused the thunder travels at the speed of light, over 186,000 miles per second (from the human perspective, that’s virtually instantaneous, regardless of your distance on Earth). But lightning’s aural component, thunder, only travels at the speed of sound, a little more than 750 miles per hour—a million times slower than light.
Knowing that the thunder occurred at the same time as the lightning flash, and the speed both travel, we can estimate distance of the lightning strike. At 750 miles per hour, thunder will travel about a mile in about five seconds: Dividing the number of seconds between the lightning’s flash and the thunder’s crash by five gives you the lightning’s distance in miles; divide the interval by three for the distance in kilometers. If five seconds pass between the lightning and the thunder, the lightning struck about one mile away; fifteen seconds elapsed means it’s about three miles away.
The 30 (or so) people killed by lightning in the United States each year had one thing in common with you and me: they didn’t believe they’d be struck by lightning when they started whatever it was they were doing when they were struck. The only sure way to be safe in an electrical storm is to be in a fully enclosed structure or metal-framed vehicle, away from open windows, plumbing, wiring, and electronics.
Unfortunately, photographing lightning usually requires being outside. And though there’s no completely safe way to photograph lightning, it doesn’t hurt to improve your odds of surviving enough to enjoy the fruits of your labor.
Most lightning strikes within a six mile radius of the previous strike. So, if less than thirty seconds elapses between the flash and bang, you’re too close. And since “most” doesn’t mean “all,” it’s even better to allow a little margin for error. Thunder isn’t usually audible beyond ten miles—if you can hear the thunder, it’s safe to assume that you’re in lightning range.
But if you absolutely, positively must be outside with the lightning firing about you, or you simply find yourself caught outside with no available shelter, there are few things you can do to reduce the chance you’ll be struck:
- Avoid water
- Avoid high ground
- Avoid exposed areas
- Avoid metal or electronic objects
- Avoid tall isolated objects such as trees and open structures (and tripods)
- Stay at least fifteen feet from other people
- Do not lie down
- If you’re surrounded by trees, position yourself near shorter trees, as far from trunks as possible
- Crouch on the balls of your feet, with your feet together and your hands covering your ears
- A lightning strike is often preceded by static electricity that makes your hair stand on end, and by an ozone smell (best described as the smell of electricity—I think of bumper cars at the amusement park, or the smell of my electric slot cars when I was a kid); if your hair starts to stand up and/or you notice a distinct odor that could be ozone, follow as many of the above steps as you can, as quickly as possible (often you’ll only have time to crouch)
Photographing lightning at night is mostly a matter of pointing your camera in the right direction with a multi-second shutter speed and hoping the lightning fires while your shutter’s open—pretty straightforward. Photographing daylight lightning is a little more problematic. It’s usually over before you can react, so without a lightning sensor to recognize lightning and click your shutter, success is largely dumb luck (few people are quick enough see it and click). And using a neutral density filter to stretch the exposure time out to 20 or 30 seconds sounds great in theory, but a lightning bolt with a life measured in milliseconds, captured in an exposure measured in multiple seconds, will almost certainly lack the contrast necessary to be be even slightly visible.
Lightning Trigger: The best tool for the job
Most lightning sensors (all?) attach to your camera’s hot shoe and connect via a special cable to the camera’s remote-release port. When engaged, the sensor fires the shutter (virtually) immediately upon detecting lightning, whether or not the lightning is visible to the eye or camera. With many lightning sensors from which to choose, before I bought my first one I did lots of research. I ended up choosing the sensor that was the consensus choice among photographers I know and trust: Lightning Trigger from Stepping Stone Products in Dolores, CO. At around $350 (including the cable), the Lightning Trigger is not the cheapest option, but after many leading lightning-oriented photo workshops, I can say with lots of confidence that lightning sensors are not generic products, and the internal technology matters a lot. Base on my own results and observations, the Lightning Trigger is the only one I’d use and recommend (I get no kickback for this). On the other hand, if you already have a lightning sensor you’re happy with, there’s no reason to switch.
I won’t get into lots of specifics about how to set up the Lightning Trigger because it’s simple and covered fairly well in the included documentation. But you should know that of the things that sets the Lightning Trigger apart from many others is its ability to put your camera in the “shutter half pressed” mode, which greatly reduces shutter lag (see below). But that also means that connecting the Trigger will probably disable your LCD replay, so you won’t be able to review your captures without disconnecting—a simple but sometimes inconvenient task. You also probably won’t be able to adjust your exposure with the Lightning Trigger connected.
The Lightning Trigger documentation promises at least a 20 mile range, and after many years using mine at the Grand Canyon, I’ve seen nothing that causes me to question that. It also says you can expect the sensor to fire at lightning that’s not necessarily in front of you, or lightning you can’t see at all, which I will definitely confirm. For every click with lightning in my camera’s field of view, I get many clicks caused by lightning I didn’t see, or that were outside my camera’s field of view. But when visible lightning does fire somewhere in my composition, I estimate that the Lightning Trigger clicked the shutter at least 95 percent of the time (that is, even though I got lots of false positives, the Lightning Trigger missed very few bolts it should have detected). Of these successful clicks, I actually captured lightning in at least 2/3 of the frames.
The misses are a function of the timing between lightning and camera—sometimes the lightning is just too fast for the camera’s shutter lag. In general, the more violent the storm, the greater the likelihood of bolts of longer duration, and multiple strokes that are easier to capture. And my success rate has increased significantly beyond 2/3 since switching from a Canon 5DIII to Sony mirrorless (more on this in the Shutter Lag section).
The Lightning Trigger documentation recommends shutter speeds between 1/4 and 1/20 second—shutter speeds faster than 1/20 second risk completing the exposure before all of the secondary strokes fire; slower shutter speeds tend to wash out the lightning. To achieve daylight shutter speeds between 1/4 and 1/20 second, I use a polarizer, with my camera at ISO 50 and aperture at f/16 (and sometimes smaller). Of course exposure values will vary with the amount of light available, and you may not need such extreme settings when shooting into an extremely dark sky. The two stops of light lost to a polarizer helps a lot, and 4- or 6-stop neutral density filter is even better with fairly bright skies (but if you’re using a neutral density filter, try to avoid shutter speeds longer than 1/4 second).
Lightning is fast, really, really fast, so the faster your camera’s shutter responds after getting the command from the trigger device, the more success you’ll have. The delay between the click instruction (whether from your finger pressing the shutter button, a remote release, or a lightning sensor) and the shutter firing is called “shutter lag.”
The less shutter lag you have, the better your results will be. The two most important shutter lag factors are:
- Camera model: It’s surprising how much shutter lag can vary from manufacturer to manufacturer and model to model. In a perfect world, for lightning photography your camera’s shutter lag will be 60 milliseconds (.06 seconds) or faster (the lower the number the better), but 120 milliseconds (.12 seconds) or faster can give you some success. The top cameras from Sony, Nikon, and Canon are all fast enough, but the latest Sonys are the definite shutter lag winner (fastest), with Nikon a not too distant second, and Canon third. And shutter lag can vary with the manufacturer’s model: While my Sony a7RII is one of the fastest cameras out there, my a7R was unusably slow, so you need to check your model. Since I don’t check every camera released, it’s possible this ranking will change well before I update this article, so I recommend that you research shutter lag for your camera model. Unfortunately, shutter lag isn’t usually in the manufacturers specifications, so it’s hard to find. The best source I’ve found is the “Pre-focused” time in the Performance tab of the camera reviews at Imaging Resource.
- Camera settings: Basically, to minimize the “thinking” the camera needs to before firing, you want to be in manual everything mode—metering and focus. If your camera offers an electronic front curtain option (as my Sonys do), use it. If you must autofocus, go ahead and do it each time you recompose, then turn autofocus off as soon as you’re focused. Though the Lightning Trigger documentation suggests Aperture Priority metering, I use and recommend Manual metering mode to eliminate any camera-slowing metering (but Aperture Priority is fine if you have a strong preference). And, also despite what the Lightning Trigger documentation suggests, noise reduction is a post-capture function that might slightly delay continuous frames, but it won’t increase shutter lag.
In addition to a lightning sensor and fast camera, you’ll need:
- A solid tripod and head: Don’t even think about trying to photograph lightning hand-held
- Rain gear that keeps you dry from head-to-toe
- Umbrella (a.k.a., Wile E. Coyote Lightning Rod) to shield your camera and lightning sensor (many sensors, including the Lightning Trigger, aren’t waterproof) while you compose and wait in the rain. The umbrella is for when you’re photographing storm cells at a great distance, such as on the rim of the Grand Canyon and the lighting is across the canyon. Obviously, when the lightning gets within 10 miles, put the umbrella down and run for cover.)
- Lens hood to shield some of the raindrops that could mar the front element of your lenses
- Neutral density filter and/or polarizer to slow shutter speed into the ideal range (1/4 – 1/20 second)
- A garbage bag (my choice) or rainproof camera jacket (haven’t found one) to keep your camera and sensor dry during a downpour
- Extra lightning sensor batteries (better safe than sorry)
- Extra memory cards: When a storm is very close or active, your lightning sensor could detect 20 or 30 strikes per minute (even when little or no lightning is visible to the eye)
- Infrared remote to test your Lightning Trigger; I sometimes borrow the remote from my hotel room, but the Apple TV remote works great and is extremely compact (fits nicely into the Lightning Trigger pouch)
- A towel
Getting the shot
Lightning is most likely to strike in or near the gray curtains (clearly recognizable as distant rain) that hang beneath dark clouds. In addition to visible rain curtains, the darkest and tallest clouds are usually the most likely to fire lightning. Here are a few more points to consider:
- The wider your composition, the greater your odds of capturing lightning, but the smaller the lightning will appear in your image.
- Identify the most likely lightning cell and find the best composition that includes it. I tend to start with wider compositions to ensure success, then tighten my composition once I’m fairly confident I captured something.
- Note the height from which the lightning originates and be sure to include enough cloud to get all of the stroke. On the other hand, don’t include too much room above the lightning—the most frequent rookie mistake I see is too much sky/clouds in the frame. The second most frequent is lightning cut off at the top. Unless the storm is too close for safety, for any given cell, most lightning will originate from about the same height above the ground.
- The best lens is usually a midrange zoom such as a 24-70 or 24-105—if you find yourself reaching for the 16-35 (or wider), you’re too close.
- On the other hand, once you’re sure you’ve captured some good strikes, try putting on a 70-200. The narrow field of view can significantly reduce the number of frames with lightning, but the ones you get will be much larger in the frame and therefore more spectacular.
- Don’t forget to try some vertical compositions. I usually wait until after I know I’ve captured some in a horizontal frame because vertical narrows the horizontal field of view and lowers the odds of success a little.
- Lightning stands out better in a slightly underexposed image. My target shutter speed is usually 1/8 second (slow enough to include multiple pulses, but not so slow that I risk washing out the lightning). When the sky is relatively bright, dropping to 1/15 or even 1/20 second can make the lightning stand out better than 1/8 (but risks losing secondary strikes). Conversely, when the sky is extremely dark and the lightning is firing like crazy, extending to 1/4 second might increase your chances for multiple pulses.
- Just because you’re standing around waiting for things to happen, doesn’t mean there’s nothing to do. Keep your eyes glued to the sky and adjust your composition as the lightning shifts, or as new activity starts elsewhere. If you wait until you hear your shutter click or someone else exclaim before looking up, you won’t see the lightning. And monitor the light—your exposure can change by several stops as the storm moves, intensifies, or winds down.
- Try not to check your captures on your LCD until you’re done (or better yet, until you upload your images to your computer). With the Lightning Trigger (and some other sensors), viewing the LCD requires turning off the sensor, which risks missing a shot (I’m pretty sure lightning waits for me to turn off my sensor), and you’ll also find that many successful captures, especially wide compositions with a relatively bright sky, just aren’t that visible on an LCD viewed in daylight anyway.
Do as I say (not as I do)
Be aware that electrical storms can move quite quickly, so you need to monitor them closely. Sometimes this simply means adjusting your composition to account for shifting lightning; other times it means retreating to the car if the cell threatens your location. No shot is worth your life.
One final note: If you check my exposure settings, you’ll see that my shutter speed here was .4 seconds, well outside the 1/20-1/4 second range I suggest. But if you look at the other settings, you’ll see that I’d opened up to f/7.1, and had cranked my ISO to 400, an indication that twilight was settling in. Successful lightning photograph is all about contrast, and the darker the sky, the better the bolt stands out, even in a longer exposure. Had we stayed past dark (and lived), we could have jettisoned the Lighting Triggers and used multi-second exposures.
Join Don Smith and me in our next Grand Canyon Monsoon Photo Workshop
Read my article in Outdoor Photographer magazine, Shooting the Monsoon
A Lightning Gallery
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