Lightning

Few things in nature are more dramatic than lightning. Or more dangerous. But 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. (But you’ll never be safer than you will be simply staying inside.)

The shocking truth about lightning

A lightning bolt is an 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.

In a thunderstorm, the up/down flow of atmospheric convection creates turbulence that knocks together airborne water (both raindrops and ice) molecules, stripping 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, with more positively charged molecules at the top than at the base.

Nature really, really wants to correct this imbalance, and always takes the easiest path—if the easiest path to electrical equilibrium is between the cloud top and cloud bottom, we get intracloud lightning; if it’s between two different clouds, we get intercloud lightning. And the less frequent cloud-to-ground strikes occur 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. Thunder travels at the speed of sound, a pedestrian 750 miles per hour, while lightning’s flash zips along at the speed of light, more than 186,000 miles per second—nearly a million times faster than sound.

Knowing that the thunder occurred at the same instant as the lightning flash, and the speed both travel, we can calculate the approximate distance of the lightning strike. While we see the lightning pretty much instantaneously, regardless of its distance, thunder takes about five seconds to cover a mile. So dividing by 5 the number of seconds between the instant of the lightning’s flash and the arrival of the thunder’s crash gives you the lightning’s approximate distance in miles (divide by three for kilometers).

Lightning safety

The 2000 (or so) people killed by lightning 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 died. So before thinking you’d like to photograph lightning, you must understand that the only sure way to be safe in an electrical storm is to be in a fully enclosed structure with plumbing and/or grounded wiring, away from windows, plumbing, wiring, and electronics. The next best option is probably a hard-top vehicle with the windows closed (myth buster: a car’s lightning safety has nothing to do with its tires).

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 ten-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 best to allow a little margin for error. It also helps to know that thunder isn’t usually audible beyond ten miles, so if you hear thunder, assume that you could be in the sights of the next lightning strike.

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, here’s some knowledge that will improve your chances:

• A lightning strike is often preceded by static electricity that makes your hair stand on end
• Avoid high ground
• Avoid exposed areas
• Avoid metal and electronics
• Avoid concrete, which is often reinforced with metal
• Avoid tall isolated objects such as trees and open structures (and tripods)
• Avoid water
• 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
• Rubber soled shoes provide no protection
• As a last resort, crouch on the balls of your feet, with your feet together and your hands covering your ears

Lightning photography how-to

If, after factoring in all the risks, you still like the idea of photographing lightning, you need to gear up. The extreme contrast between darkness and brilliant lightning means 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 more problematic. It’s usually over before you can react, so any success just watching and clicking is probably dumb luck. And using a neutral density filter to stretch the exposure time out to multiple seconds sounds great in theory, but in daylight, a lightning bolt with a life measured in milliseconds, captured in an exposure measured in seconds, will almost certainly lack the contrast necessary to show up in an image.

Lightning sensor

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 immediately upon detecting lightning, whether or not the lightning is visible to the eye or camera. With so many lightning sensors from which to choose, I did lots of research before buying my first one. 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 years 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. Based 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 LT will probably disable your LCD replay, so you won’t be able to review your captures without turning it off. You also might not be able to adjust your exposure and perform other camera control tasks with the Lightning Trigger connected—the amount of limitation varies with the camera.

The Lightning Trigger documentation promises a range of at least a 20 mile, and after using mine at the Grand Canyon for years, I’ve seen nothing that causes me to question that—if anything, without actually testing it, I’d guess that its range is at least 30 miles. The LT documentation 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 anywhere in the general direction of my composition (a lightning sensor has no idea how your composition is framed), I estimate that my 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, something I’ve observed can be at least partially storm specific—some storms seem to have shorter duration lightning strikes than others. 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 noticeably increased since switching from a Canon 5DIII to the much faster Sony Alpha bodies.

The camera matters

Lightning is fast—really, really fast—so the faster your camera’s shutter responds after getting the command to fire, the more success you’ll have. The delay between the click instruction (whether from your finger on the shutter button, a remote release, or a lightning sensor) and the shutter firing is the “shutter lag.”

In general, interchangeable lens cameras (mirrorless and DSLR) have the fastest shutter lag. But even with an ILC, it’s surprising how much shutter lag varies from manufacturer to manufacturer, and even between models from the same manufacturer.

Ideally, your camera’s shutter lag should be no slower than 60 milliseconds (.06 seconds), but 120 milliseconds (.12 seconds) is generally fast enough. Most of the top cameras from Sony, Nikon, and Canon are fast enough—currently, Sonys are fastest, Nikon is a close second, and Canon is third.

And shutter lag can vary with the manufacturer’s model: While my Sony a7RIV may be the fastest camera out there, my original a7R was unusably slow, so you need to check your model’s shutter lag.

Unfortunately, shutter lag isn’t usually in the manufacturers’ specifications. The best source I’ve found is the “Pre-focused” time in the Performance tab of the camera reviews at Imaging Resource.

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Other equipment

In addition to a lightning sensor and fast camera, you’ll need:

• Solid tripod and head: Don’t even think about trying to photograph lightning hand-held. And contrary to popular belief, a carbon fiber tripod is no safer than an aluminum tripod.
• 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, the lighting is more than 10 miles away, and the rain that’s falling on you is coming from a cloud with no sign of electrical activity or potential. 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)
• Garbage bag (my choice) or rainproof camera jacket (haven’t found one I like) 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)
• Towel 

Lightning app

I’ve used a few lightning apps, but I finally think I’ve found one worthy of recommending: My Lightning Tracker. I find it easy to use, and reliable. I have the “pro” version, which just means I paid a few dollars so I don’t have to see ads.

My Lightning Tracker has too many useful features to list here, but the most important thing it does is give me a good idea where the lightning is firing now (as long as I have a cellular or wifi connection), and how far away it is. It will also alert me of any strikes within a user-specified radius.

If I wait until I the app tells me there’s lightning nearby before heading in that direction, I’m often too late. So I also appreciate My Lightning Tracker’s option to view the local weather radar, which helps me identify potential active storms before the lightning starts.

Getting the shot

Even if you can photograph lightning from your front porch, it’s usually best to pick a nice scene, then monitor the weather so you can be there to capture lightning with a great foreground. I strongly recommend that you scout these lightning scenes in advance, not just for possible compositions, but for safe places to set up, escape routes, and a place to retreat to if the lightning gets too close. I try never to shoot more than a quick sprint from my car.

Once you’re there, don’t wait until you see lightning before setting up your gear. If the sky looks even a little promising, get everything ready: tripod out, camera and lens mounted, lightning sensor attached. Then test your lightning sensor to make sure it fires your camera—I can’t tell you how easy it is to overlook one little thing and wonder why the lightning is firing but your camera isn’t. I test my Lightning Triggers with a TV remote, or with the flash from my iPhone camera.

The trickiest part of lightning photography is getting the exposure right while using best shutter speed. Too fast and you risk missing all of the strokes; too long and you risk washing out the lightning. The ideal lightning shutter speed range is 1/4 to 1/20 second—shutter speeds faster than 1/20 second risk completing the exposure before the secondary strokes fire; slower shutter speeds tend to wash out the lightning.

My personal sweet-spot is around 1/8 second, but I’ll shoot for the faster end of my ideal shutter speed range when there’s lots of sunlight, and stretch the exposure out toward 1/4 second when dark clouds rule the entire scene. And I’ll go even longer than 1/4 second when twilight darkens the scene further.

To achieve daylight shutter speeds between 1/4 and 1/20 second, I often need to use a polarizer and set my ISO to 50, with an aperture of f/16 or 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 cut by a polarizer helps a lot, but 4- or 6-stop neutral density filter is even better with dealing with fairly bright skies.

When the sky is relatively bright, dropping to 1/20 second can help the lightning stand out better than 1/8 second, 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 capturing multiple pulses.

Composition

Lightning is most likely to strike in or near the gray curtains that hang beneath dark clouds (clearly recognizable as distant rain)—not only near the center, but often on the fringe or just outside. And the darkest and tallest clouds are usually the most likely to fire lightning. If you’re in the storm that you’re photographing, you’re too close.

The best lens for lightning is usually a midrange zoom, such as a 24-70 or 24-105. If you find yourself reaching for your 16-35 (or wider), you’re too close.

I generally start fairly wide to increase my margin for error (to avoid missing a bolt just outside my frame), but once I’m sure I’ve captured some good strikes, I often tighten my composition. While this narrower field of view can reduce the number of frames with lightning, the ones I get are much larger in the frame.

Here are a few more composition points to consider:

• Identify the most likely lightning cell and find the best composition that includes it.
• The more resolution you have, the looser you can compose, then crop to the best composition later.
• Don’t include too much room above the lightning—the most frequent rookie mistake I see is too much sky/clouds in the frame. I like my lightning bolts to originate just below the top of my frame.
• The second most frequent rookie mistake I see is lightning cut off at the top. Note the height from which the lightning originates and try to include enough cloud to get the stroke’s origin point. And if you’re really wide and still can’t get all the lightning, run! (Like I did after the image below.)
• Don’t forget to try some vertical compositions.

There’s a lot of standing around while photographing lightning, but storms move, so the more you can keep your eyes on the sky (instead of your phone), the better you’ll be at keeping lightning in your frame as the storm moves, and knowing when the activity is picking up or winding down. The light can change by several stops as the storm moves, intensifies, or winds down, so check your exposure frequently. And monitor your surroundings for active cells moving up behind you.

Be aware that electrical storms can move quite quickly, and more than one cell can be active in a given area, so monitor the sky closely—not just the storm you’re photographing, but scan for potential cells that could be sneaking up on you. 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.

Here’s an article by one of my workshop students describing a great processing technique for enhancing your lightning.

Join and me in my next Grand Canyon Monsoon Photo Workshop

Read my article in Outdoor Photographer magazine, Shooting the Monsoon

Workshop Schedule || Purchase Prints

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A Lightning Gallery

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