During the past year, I’ve been sharing many of my astro-landscapes and one thing that people have repeatedly asked me is how do I get my foregrounds so detailed and clean. Usually the problem photographers have when shooting the night sky is that their foregrounds are too dark, too noisy, or both.
There are many methods to get detailed, well-lit (but not overly bright) foregrounds that result in clean images. However, they all boil down to collecting more light so that you don’t have to increase the exposure as much in post and hence reduce the impact of noise. Here are some methods that I’ve used:
Blue hour blend
Take a shot of the foreground during blue hour (the time after the sun has set but before it’s completely dark). Don’t move your tripod or your camera and then expose for the Milky Way once it gets dark. Blend your exposures in photoshop.
As a bonus, during blue hour you can usually use a smaller f-stop and get deeper depth of field. In some cases this can eliminate the need for focus stacking completely or at least make focus stacking easier because you will need less frames.
This is corresponding foreground shot:
Here is another example taken in a mountain meadow. I shot the lupines during blue hour (needed a 3 image focus stack) and the Milky Way a few hours later. Doing the focus stack of the lupines at night would have been impossible.
Shooting during blue hour
The Milky Way actually starts to become visible during blue hour and you can take your shots for both the foreground and sky at the same time. You won’t have as much contrast between the Milky Way core and the rest of the sky but the scene can still look very nice.
For coastal shots like this example, it helps to shoot when the humidity is very low. Less water moisture in the air means greater clarity and more visibility. For people in SoCal like I am, this often means shooting when the Santa Ana winds are blowing. To judge humidity, I look at the dew point temperature (lower is less humid and better).
Here is the sky shot of the Milky Way core taken about one hour after sunset and you can still see the warm colors on the horizon. Note that the photo is intentially left flat (I will typically blend and pano stitch first with a flat/neutral version of the image and then add contrast and creative adjustments).
Shoot the foreground with moonlight
You don’t always have to shoot the Milky Way during the new moon. You can go shooting when the moon is up and use moonlight to illuminate the landscape. For example, in this shot of Font’s Point, I took a picture of the foreground at about 12 AM with the moon 60% illuminated. I then waited until after the moon had set to shoot the sky and Milky Way (about 3 AM).
This is the foreground with default settings in Lightroom. The exposure settings were ISO 640, f/4, 61s. Without the moonlight, I’d probably need exposure times of perhaps 10-20 minutes to capture this much light.
If the moon is rising during the night, you can also shoot the sky first and then do the foreground afterwords. It’s also possible to shot both the foreground and sky while the moon is up, but the stars will be dimmer due to the moonlight. I usually check this site for moon rise/set information.
Low level lighting with dim LED panels
Another method is to bring your own lights. I personally like to use very dim stationary LED lights that I put up on a light stand. The brightness is set so low that you can use the same exposure for the sky and foreground and you are not required to blend. When balanced properly, you should barely be able to see the effect of the light panel with the naked eye.
The light stand lets you raise your panel and prevent strong shadows on the foreground. You can also feather the light by pointing it partially away from the subject. If your light is too bright (a common problem with most panels) you can either add extra diffusion by placing a cloth over the front or try bounce lighting by pointing your light at a large rock wall or other surface so that your subject is lit indirectly.
Here is a lighting diagram for the above shot:
Another example at the Racetrack in Death Valley. In this case, the light was on a stand just a few feet to the right and behind the camera. Having the light close results in greater falloff on the Playa surface as we go further into the background.
For this last photograph, I used two LED lights. One for the wall and another light placed maybe 50 yards to the side illuminating the mountain in the background.
Usually I put my lights on a stand but you can also set your camera to a minute or two exposure, and walk around with the panel lighting just the areas you need.
Some people like using a flashlight to light paint but I find that it’s very difficult to get even lighting without hotspots. It’s also not repeatible if you want to do image stacking. For more information check out lowlevellighting.org.
Long exposures with Starlight
The previous methods all involved getting more light, either from the fading sun, the moon, or bringing it yourself. This method is to simply use much longer exposures with star light. For example, I might take a 20s shot for the sky and blend it with a 5 minute shot for the foreground. Usually your exposure for the foreground needs to be at least 4-8x longer than the sky depending on your tolerance for noise.
Here is the foreground shot at ISO 3200, 16mm, f/4, 302s.
Here are the sky and foreground shots for the chimney image. When photographing it’s best if you do not move the tripod or camera. This will make the blending of the two exposures much easier.
For this last shot, I used an LED light to illuminate the inside of the fire place but not the outside.
Even with the longer exposure, you may find that the foreground is still somewhat noisy. In this situation I will often stack many exposures and average them to reduce noise. For example, I might take 5-10 foreground shots load them in photoshop and take the average (median blend) to get a cleaner image. As you might expect, it can take quite a long time to collect all your base shots for stacking and I thus rarely attempt more than one or two compositions in a night.
There are many different methods for lighting the foreground and I encourage you to experiment with the different techniques. They all have their pros and cons, and I like to choose the method based on the scene and conditions. Sometimes you don’t have the option of using moonlight or getting there during blue hour so bringing a panel helps. Other times you might have to bring a panel because you’re shooting through a forest canopy or out of a cave where there is very little natural light.