Go online the day after a meteor shower, and you’ll find images of the night sky plastered all across social media. A few years ago, the photographers behind these pictures were limited to those with the best equipment, but today you can take great long-exposure shots with almost every smartphone and DSLR—as long as you know a few tricks. And with a new meteor shower, the Camelopardalids, set to hit our skies Friday night, it's the perfect time to brush up on long-exposure photography. Here are a few tips for shooting well in the darkness.
When you leave your camera’s shutter open for an extended period of time, allowing more light to hit its sensor, you’re taking a long-exposure photograph. Long exposures are most frequently used in low-light situations to either illuminate dark settings or to create a “light painting,” wherein a light source move throughout the frame, creating a line or shape out of that light.
Shoot long-exposure photography with a DSLR
To shoot night skies with your DSLR, you’ll want a lengthy shutter speed, a wide aperture (which means a lower number, say F/4 instead of F/11), and a higher ISO to let in light. When you pair the three, it provides a perfect trifecta for your camera to properly expose your image. Shooting in an environment with existing light (buildings/streetlamps/etc) does require an adjustment to these settings, as you will have more light in your area that will become overbright as you expose darker areas. One solution is to layer multiple exposures during post processing, to have a well exposed image in all areas.
When you’re shooting long exposures of stars, you’ll notice that they start to move and create startrails or lines in your image (this occurs after about a 20 second exposure). Not everyone wants this, so be sure to adjust your settings accordingly.
Most traditional DSLR cameras let you place your camera in Manual mode to control the exposure and aperture separately; I prefer this when experimenting with low-light photography. If you’d rather not mess with too much on your first outing, however, most cameras also offer the AV or TV mode, which allows you to manually control either aperture or shutter speed while automatically adjusting the other.
Once you’ve decided what mode you’re shooting in, you’ll want to further tweak a few things. First, shoot with your autofocus and image stabilizer turned off; otherwise, your camera will fight to find a spot to focus on while trying to correct the slightest movement in the frame. It’s a waste for both your battery and your shooting time. Additionally, set your lens focus set to infinity to have the best shot at getting a clear, focused picture.
Shoot long-exposure photography with an iPhone
While that iPhone’s default Camera app doesn’t allow you to fiddle with the settings you need for proper long-exposure photography, there are several third-party apps made with this purpose in mind.
Despite that, I prefer LongExpo, as the app comes with easy-to-use presets for Standard, Low Light, and Light Trail photographs. Time Exposure takes a bit more getting used to, as it offers more technical presets. Neither are perfect replacements for a DSLR: LongExpo occasionally distorts images and loses detail when capturing brighter sections, as I discovered while shooting a building with lights; the light fixtures turned into giant glowing orbs. In contrast, Time Exposure tends to shoot much darker images, requiring a longer exposure time to match up to the brightness in pictures I took with LongExpo.
Gear for your DSLR or smartphone
As night skies vary from area to area, there’s no perfect setting for long-exposure photographs, so you’ll want to tweak and test your setup when you arrive. Whatever you decide, I highly recommend picking up a few pieces of gear to make your shooting experience more enjoyable: a tripod, cable release cord, and (if your picture calls for it) an external flash.
Tripods: It is a very rare person who can keep themselves—and in turn, their camera—still for up to a minute so that they can take a perfectly-focused long-exposure image; the slightest movement will result in what looks like a double exposure, with the same scene bouncing around the frame. As such, for the 99.9 percent of us whose handheld photographs come out horribly blurry, a tripod is essential. This is doubly important for people shooting with an iPhone, given the device’s light weight; luckily, there are plenty of small gadgets available that can attach to a regular tripod, like Studio Neat’s Glif.
Cable release cords: Your DSLR’s lowest possible shutter speed is the “Bulb” setting. While on Bulb, your camera’s shutter will remain open for as long as you are holding down the shutter release button. Even with a tripod to steady most of your camera, interacting with it in this manner may shake it and blur your image. One great solution for this problem is a cable release cord—an inexpensive addition to your gear. If you’re using an iPhone and don’t want to spend any cash, you can always use the Apple headphones’ volume control button as a cable release; there are also several third-party cable releases for sale on sites like Photojojo.
Why bring a flash to a night sky session? Most budding photographers know that landscape photographs won’t be improved with a flash, no matter how powerful. But if you’re trying to shoot a portrait behind the night sky, you can use a flash to illuminate a portrait while properly exposing the evening sky. Just make sure your subject’s willing to stay still.
Updated on 5/27 at 10:22 a.m. ET to correct an error in calculating aperture.