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How to Expose the Foreground in a Nightscape

In past tutorials, we’ve discussed planning imaging sessions, taking into account the weather and positioning of celestial objects. We’ve talked about how to properly expose the sky while avoiding star trailing. What we haven’t talked about yet is the other half of a nightscape; the foreground. In this tutorial, I share six techniques I’ve learned over the last couple of years that you can use to ensure your foregrounds compliment the starry skies in your images.

Method 1: Silhouettes

The simplest way to include a foreground in your image is to not expose for it at all while exposing solely for the sky. What you’re left with is an image of the stars with a mostly-black foreground.

Figure 1: Ponderosa pines and the surrounding hills silhouette the night sky near the Pecos River in north-central New Mexico. Shot with a Canon EOS 70D and Canon EFS 10-22mm F/3.5-4.5 zoom lens @ 10mm, F/3.5, 20 seconds, ISO 6400.

When I first started shooting the night sky, most of my images turned out this way, more because I was too excited about seeing the stars to even consider the foreground! That’s not at all to say that a silhouetted foreground can’t be striking. This is still one of my favorite images, but it turns out you can do much more with a little experimentation.

Method 2: Light Painting

Artificially lighting a scene can add an interesting dimension to your shots. Like anything else, lighting can get complicated (and expensive) very quickly, but you don’t have to invest in a multi-point remotely-triggered lighting rig. Here’s one scene I “painted” with a flashlight I found in the dresser of my hotel room.

Figure 2: The Milky Way shines through a hole in the rock at Devil’s Punch Bowl near Newport, Oregon. Shot with a Canon EOS 6D and Rokinon 24mm F/1.4 lens. Several exposures of the same scene taken at F/1.4, ISO 6400, 20 seconds, were composited in GIMP to create this image.

If you know how to composite images in GIMP or Photoshop and have time to try casting light from different positions during your session, you can “paint” your scene with almost any external lighting source. Just start your long exposure, then “paint” the scene during the shot as if you were holding a paint brush in your hand. It will take a little trial and error to get it right, but you can get great results without breaking the bank.

Method 3: Moonlight

If the moon is up during any part of your session, you can use it to your advantage. It’s a little trickier to illuminate a scene with moonlight when compared to sunlight because the moon’s overall brightness depends on its phase, but it’s still possible. Here’s a single shot I took during the Perseid Meteor Shower of 2016.

Figure 3: A Perseid meteor streaks overhead during the 2016 Perseid Meteor Shower. Shot with a Canon EOS 6D and Rokinon 14mm F/2.8 lens @ F/2.8, ISO1250. One 20-second shot.

The first half of the evening was bathed in light from the first-quarter-moon, but the meteors that fell were bright enough to overcome the moon’s glare. I had planned to shoot the fire first, then shoot meteors all night and composite them in later, but I got lucky and captured this beauty on the first shot. It ended up being an even luckier shot because my lens fogged up shortly afterwards and I didn’t capture another meteor all night!

Method 4: Light Pollution

Most astrophotographers would agree that light pollution is generally a terrible thing, but sometimes it can make lighting up a scene much easier than waiting for the right conditions. Here’s one such example.

Figure 4: Light pollution (left side of the frame) from the nearby city of Truth or Consequences, New Mexico, illuminates Turtleback Mountain, which rises 1600 feet above the desert floor. Shot with a Canon EOS 6D and EF 35mm F/1.4L lens @ F/2.8, ISO 6400, 15-second exposures. A total of 16 shots were stitched to make this panorama.

Normally, to illuminate a mountain, you would first have to shoot the scene for the foreground which can take ten times as long as the sky, then shoot the entire scene again for the stars. Fortunately (for this shot, anyway), T or C was just bright enough to illuminate the mountain without washing out the entire Milky Way, saving me a ton of time in post-processing. It isn’t very often that light pollution works out so perfectly, but in this case, it did.

Method 5: Starlight

In most cases, you won’t have a perfectly-positioned city to illuminate your scene. Fortunately, it’s possible to use starlight! Here’s an example of a foreground lit up by the Milky Way itself.

Figure 5: A creek downstream from Fenton Lake, New Mexico, reflects light from the Milky Way. Shot with a Canon EOS 6D and EF 16-35mm F/2.8L zoom lens @ F/2.8, ISO6400. A single 20-second exposure was used for the stars and a second 2-minute exposure was used for the foreground.

The biggest issue with shooting the foreground this way is that you must expose the ground on a moonless night up to ten times as long as the sky to be able to see it. Most cameras will only allow you to do this in “Bulb” mode. Such long exposures can lead heat buildup in the sensor, which can cause the image to become very noisy. I had to edit out far more “hot pixels” in the foreground of this image than I normally would. Another issue is that, at such long exposure times, you’re much more susceptible to passing breezes, which can cause any foliage in your image to move through the exposure. Still, if none of the other methods mentioned so far is an option for you, starlight can definitely be used to illuminate the foreground.

Method 6: Twilight

A final, tried and true means of illuminating your foreground is to shoot it during astronomical twilight. That is, the period of time where the sun has set but the sky is not yet completely dark (conversely, you can also shoot during morning twilight). The light from the sky during this time is particularly nice because it diffusely illuminates everything in the scene; there are no hard shadows. Here’s a recent example of a shot with the foreground taken at twilight and the sky taken later on in the night.

Figure 6: The Milky Way rises over the burn scar left by the Dog Head Fire near Tajique, New Mexico. Shot with a Canon EOS 6D and EF 16-35mm F/2.8L zoom lens. The foreground is a 30-second shot taken at F/4 and ISO1600. The sky was exposed for 30 seconds at F/2.8 and ISO6400 and tracked at half the sidereal rate with an iOptron SkyTracker. Shots were manually merged in GIMP.

What makes this method perhaps more difficult than the rest is that it requires a lot of patience if the desired celestial objects aren’t well-positioned immediately after evening twilight or immediately before morning twilight. The weather can change in the hours between foreground and sky shots. It can be tough to judge just how bright or dark your foreground should be to match well with the night sky. It’s also a bit of a bummer that you cannot move the camera in-between these shots, as doing so will ruin the alignment between foreground and background. But I’ve found the results of this method to be the most desirable out of the six I’ve tried so far.

Final Thoughts

To be honest, I didn’t realize how many different ways there were to illuminate a scene when shooting the stars until I wrote this article. I’m surprised there are so many, and I hope I can get better at each now that I’m acutely aware of them. Are there any other ways you can think of that I haven’t mentioned here? Let me know in the comments below!

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