Lightning photography 101

Lightning photography is one of the most addictive and rewarding photographic subjects one can attempt to capture. It is actually a remarkably simple process, and with the right knowledge, amazing images can be made by anyone. This guide will be focused on nighttime/dusk photography, which uses long exposures to capture the full lightning strike including the stepped leaders, doing this during the day isn’t practical due to too much available light. I’ll also add here this guide isn’t for a complete newbie in the photography world, at least a basic understanding of the exposure triangle and composition are worth learning if you are starting off in the world of photography.

So what is required to capture lightning?

Gear

The gear one needs is fairly straight forward, and can be picked up remarkably cheap these days.

A DSLR is generally the best way to go for lightning photography. Whilst higher end compacts can still produce good results, a DSLR allows the greatest amount of control, which makes obtaining the desired shots easiest. Any modern DSLR is more than capable of producing professional results. The beauty of DSLR’s over the days of film, is post processing is MUCH easier and hundreds of high quality images can fit on one SD card.

Next comes the lens. Most cheaper DSLR’s come with a standard kit lens, and whilst in the early days of digital photography kit lenses were usually rubbish, modern ones are more than adequate for the job. Generally however, the biggest issue with the kit lenses is the short manual focusing distances, making precise focus difficult in low light. Given focus is such a key point to quality lightning images, it can be worth investing in higher quality lenses for this reason alone. However if budget is an issue, the kit lens can still work fine, though I would expect a greater rate of out of focus images.

Tripods are very important for image stability, and it is worth investing in at least a half decent tripod, something better than a 30 dollar one. For around 100 dollars, solid ones can be bought however they are usually fairly heavy. Lighter tripods with better stability and precision can be purchased at a much greater cost.

Finally a remote shutter release is useful but not absolutely essential. Ideally you want to maximise image stability as lights on the horizon can form lines if the camera is moved even slightly during an exposure (or even worse, when a bolt drops right as you click the shutter causing it to blur). If no shutter release is available, you can always use the 2 second delay to counter the movement from touching it. Take note however that the longer your shutter is exposing, the less chance of missing a bolt!

Capturing the image

Depending on your goals, you can aim to capture lightning alone, or you can encompass lightning into an existing landscape. For truly striking images, having a good composition is tends to be best, as it is this that separates one lightning image from another. Aiming for lightning alone tends to involve a lot of adjusting composition and often panning with a storm. Personally I only tend to do this when a storm is some distance away, when the foreground is likely to be black. The other option which tends to produce less lightning images overall, but higher quality ones is to set up your composition beforehand, and wait for the storm to produce lightning within the frame. This very much is a case of easier said that done however, as waiting for a storm at a given location is always a risk…more often than not my compositions are set up on a whim, as I often need to chase the storm cell.

For the most part, nocturnal storms in SA are nearly always mid level based, and produce the clear air, quality bolts out ahead of the cell. This is ideal in reality, as if you place yourself well, the storm will track straight towards you. During the day however, especially on big storm days (surface based), some of the best CG and crawler action is behind storm complexes. Realistically though, it takes little knowledge to figure out where the lightning will fall, look for rainshafts, especially freshly forming ones as near them is where the lightning is likely to occur. We do get positive lightning bolts in South Australia which can land quite a distance from the storm itself, however storms producing large numbers of these are few and far between.

 

Focus

Focus is perhaps the most important variable in lightning photography, as having the focus even slightly out dramatically reduces the impact and sharpness of a lightning bolt. Too often I have seen people ruin what would have been a great shot, simply by not taking the time to get the focus right, it is worth the time believe me! Infinity seems to be the best distance to focus on, and achieving this at night can be done in a few different ways. It is generally easier to use live view to obtain highly accurate focus.

  • If the moon is visible, using liveview zoom, one can focus very effectively to infinity using auto focus onto the moon. Manual focus is easily achieved using the moon also. In the sticks, this is often my first preference as it is a reliable method and very quick.
  • If in a city or town, one can simply use auto focus on a lit object (works best with sharp edged objects with plenty of contrast) at a distance, generally of at least 50 metres. For anyone shooting above or in a city this is usually the easiest option.
  • Using the infinity mark on a lens. This can be reasonably reliable however the mark is often slightly out, and as I’ve already said even a slightly out of focus image loses a lot of impact. It is worthwhile checking where true infinity is during the day and taking note of it’s location on the lens. Be aware it can vary slightly between apertures. Depending on the lens this is a viable option, my 10-22mm lens is spot on the infinity mark.
  • Bright ‘stars’ such as Venus can be used to achieve focus however this method requires a little more time and tinkering. It involves manually exposing a star so that it is just visible in live view near infinity. It is then a matter of shifting focus until the star is at its brightest. The brighter the star, the closer the focus is to infinity.
  • If all these options are failing to produce good focus, and there are absolutely no light sources nearby, one last final option is to use car headlights to attempt to illuminate distant objects and focusing on them. One can then tap the focus a little further back, especially if using a telephoto lens, to reach a point close to infinity. I find road signs can bounce the light nicely and can be used to achieve good focus. If using a wider angle, this tap towards infinity is usually unnecessary as the depth of field of wider focal lengths is greater.

It is worth after capturing the first bolt, to review the image on the camera to check it is adequately focused. Zooming in on the base of the bolt and looking for ground features is generally best, as telling whether a bolt itself is in focus can be difficult. Remember after finding infinity to put the lens onto manual focus!

Exposure

Exposure is a difficult variable that improves with experience. Some types of lightning, like the staccitos we often see in South Australia require quite open apertures and even higher ISO’s to be exposed correctly. It isn’t unusual for a storm only 10km away to still require f/4.5, ISO 100 to be exposed bright enough. At the same time I have had nights where f/14 ISO 100 is needed to avoid blow outs at the same distance. Lightning inside rain curtains will require less light as they bounce the light through the drops and are much brighter.

ISO is usually best set at 100 to reduce noise, however sometimes the lack of sensitivity can mean needing to open the aperture up. For distant lightning this generally isn’t an issue, however if you are trying to incorporate a foreground, the lack of depth of field can be an issue. Given how good DSLR’s have become, it isn’t unreasonable to use up to ISO 400 (or 800 on full frame cameras) these days, although longer than 30 seconds at these ISO’s can become quite noisy.

Shutter speed is one of the least important variables, and generally this is the variable I use to expose the foreground. If shooting a city scene, I am often limited to 30 seconds, sometimes even less with distant lightning. On moonless nights or if shooting in the country, exposures can potentially be almost limitless. A factor to keep in mind is if stars and cloud are in the image, star trails will form, and spontaneous flashes of lightning some time apart can cause ghosting in the clouds, most prevalent on dark nights.

Aperture is the key to exposing lightning bolts, unless you are shooting a storm quite some distance away, the ISO is usually set at 100, the shutter speed is variable so the only control left is the aperture! As bolts get closer, the aperture will generally narrow. Between 10-20km, which is the ideal range to be from a storm IMO (lack of rain, less risk of being struck + much easier to gauge where bolts will drop as opposed to the storm being on top of you), the aperture for typical South Australian nocturnal storms is generally between f/4-f/9 at this distance. Once again this comes very much down to experience. Don’t be disheartened if you blow out some shots out or some are badly underexposed, given the random nature of lightning, this is bound to happen sometimes.

Focal length is very dependent on your goals, and the distance from the storm. If you are trying to ‘snipe’ bolts as I like to call it, tight framing of the lightning active part of the storm can require high focal lengths at times. Whereas perhaps if you want a reflection off a lake, an ultra wide angle might be used. Personally, I’ve used everywhere from 10-100mm (1.6x crop) for lightning with good results.

So the general method of setting up and deciding on exposure goes as follows.

  1. Set up the composition
  2. Find infinity focus
  3. Determine the necessary aperture for the depth of field for the scene, taking into account what ISO and exposure will be needed to expose both the foreground and the lightning properly. E.g. an ultrawide shot, with the closest foreground point a metre away, with lightning 10km away and a half moon might require f/10, ISO 400, 30 seconds. Whereas an image shooting lightning over the ocean at 30km in clear air might need f/2.8, ISO 100, in this case, the exposure wouldn’t matter.

If all these steps are done correctly, and you are blessed with a magnificent lightning bolt in your frame, then high quality lightning images will result.

Shooting at sunrise or sunset can be some of the best times to capture lightning images, however due to the amount of light still available, using the longer shutter speeds needed can result in blowouts unless the aperture is very narrow, resulting in diffraction and bolts lacking detail in the stepped leaders. This often means shooting exposures as short as less than a second in quick succession which chews battery, something to keep in mind if storms are expected to continue into the night. I find shooting aperture priority is a good method at this time of day. Generally you set both the aperture and ISO, and allow the metering to determine the shutter speed for the scene. To extend the shutter speed as long as possible to increase the chance of capturing a bolt, it is worthwhile biasing the exposure up to +1 stops which doubles the exposure. Just be sure you aren’t pushing the histogram too far to the right to avoid blowouts. Setting the lowest ISO ( which is 100 on most entry level cameras) and stopping right down (I generally tend to avoid dropping below f/16 which renders bolts skinny and causes diffraction) is a good start, especially right at the point of sunset, and can yield exposures of up to one second. This method allows quick and accurate metering of what is a rapidly changing scene, with light dropping more than a stop every 5 minutes. As it darkens and the aperture priority starts choosing longer exposures, you can wind the aperture down gradually, choosing a compromise between image quality and chances of capturing bolts. I like to keep the exposures around 10 seconds generally at this time of day.

A final key point to lightning photography is to shoot in RAW. This is incredibly important as the brightness of bolts can vary dramatically and having the ability to pull highlights or shadows makes a huge difference to the final image. It is quite rare that you would produce a perfectly exposed picture as a straight out of the camera jpeg. Even if you are most comfortable with the camera producing Jpegs, I urge you to shoot both RAW + Jpeg as if down the line your post processing skills improve, you’ll be able to  come back and improve them. Shooting RAW also simplifies the capturing process as you don’t need to worry about odd white balances causing strange colours in images (this often occurs when shooting around artificial lighting) as it can be easily adjusted afterwards. I’ve avoided even mentioning white balance for this reason alone, there’s no reason to shoot jpeg when shooting lightning!

Stacking images

Stacking images can be a very useful way to bring more lightning strikes into an image, with minimal loss of image quality and thus can be a very useful tool. Some people worry about the ethics behind stacking lightning however I personally have no problem with the technique, if used in moderation.

Image stacking allows more lightning strokes in an image without the limitations of overexposure or diffraction caused by low apertures. It also reduces the noise of an image. For the final image, stacking 4 15 second exposures produces essentially the same image that leaving the shutter open for 60 seconds would. The difference however is one has more control over aperture and exposure length which can make a huge difference in image quality. Exposing a scene beyond 30 seconds causes noise to start creeping into an image, which after a few minutes, often ruins the images quality. Stacking is a good way to work around this issue. Likewise if one is shooting a city scene, the foreground is often many times brighter than the sky, and trying to get a large number of strikes in one image can be nearly impossible without blowing the foreground out. Even moonlit nights can blow the foreground out unless one drops the aperture which reduces the impact of strikes.

Whilst image stacking is a useful tool, I too often see people stacking high numbers of images resulting in all sorts of artifacts and strange colours in the image. One needs to decide for themselves the point at which it becomes too much, personally I never stack more than a few images as artifact issues often present beyond this and the image starts to look a bit ridiculous and fake. Be aware that it is fundamentally important that the camera is not moved between exposures as images may struggle or even fail to align in post processing. It is in this circumstance a shutter cable comes in very useful.

Programs such a Startrails (free) work well for stacking. I wont go into the details of the actual process as using the aforementioned program is an easy process. On Adobe Photoshop greater control can be had with manually stacking images, however this is a more complicated process.

An image stack of lightning I recently created. These bolts occurred 15 seconds or so apart in separate exposures. Is this image unethical? I don’t consider it that way, had I clicked my shutter 15 seconds later I would have caught the image almost exactly as shown. Given the time difference between the bolts this was a very easy blend.

Some bolts during blue hour. This image was taken at iso 100, biased +0.7 stops, f/14, 4 seconds. The bolts would have had more impact if the aperture were larger however I needed the shutter quite long as the bolts were only semi-frequent.

An example of ‘sniping’ bolts. Taken from my roof using 160mm equivalent panning along the base of a storm some 45km away.

Letting the bolts fall into a pre-conceived composition is more hit and miss, but can the results are often worth it.

Letting strikes fall into a pre-conceived compositions has produced some good results for me, but truth be told I often fall into the trap of lightning dominant images. It’s a difficult thing ignoring bolts in favour of a more lucky shot, especially when storms are so infrequent where I live. Once again it all comes down to ones personal pursuits.

 

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One Response to Lightning photography 101

  1. Very interesting post! I’m no photographer, but the info was great!

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