Photographing the Milky Way behind Mobius Arch in the Alabama Hills near Lone Pine, CA seemed like a worthy challenge. The arch and other rocks nearby are compositionally complementary to the always awesome Milky Way. Some lighting seemed the optimal method for making the foreground subjects visible in the image, and this time, low-level (low intensity) lighting was the strategy implemented.
Low-level lighting involves setting up continuous lights on the foreground. The requirements for these lights include:
A quality spectrum output is paramount. Just as you care that the entire light spectrum is evenly transmitted through your lens, you care that the full spectrum of light is provided in the first place. Correcting light spectrum issues during post-processing can be a huge, time-consuming challenge, especially if the entire image does not share the same deficiency (such as the sky). Look for lights with a CRI specification of 95 or higher.
While having the entire visible light spectrum equally provided is important, additionally helpful is the ability to continuously adjust the light's color temperature output, enabling emphasis of the foreground feature's color and matching the desired night sky color temperature — try 4000-4500k. Especially important is having warm settings available. Look for lights providing minimally 3200k, and lower is better.
Most night sky photography involving foreground lighting is not done in the back yard. Thus transportation and, often, hiking are involved. Especially when using multiple lights, compactness is a desired trait.
Yes, reducing the size of the light causes the lighting to be harsher, producing a sharper transition into shadows. However, the size of night sky foreground subjects is usually quite large, and the lights are typically placed at a distance from the features, making the size difference between portable lights typically irrelevant.
Compactness means less storage space is required.
Compact lights usually feature light weight, also a feature desired for transport.
Another important low-level lighting feature is continuously adjustable brightness. Light intensity falls off at an inverse-squared (very fast) rate, so the intensity required for one situation can be vastly different from another. For example, the light behind the arch in this image was much closer than the light illuminating the entire scene. Look for a light that provides 1-100% intensity adjustment control in small increments (1% is ideal).
I saved a key requirement for last. Unless lighting distant mountains, the light output needs to be extremely dim.
No manufacturers are saying, "Let's see how dim of a light we can make", and nearly everyone wants their lights to be as bright as possible. Indeed, brighter is better for most photography and videography lighting applications. Ask lighting experts for the dimmest light recommendation, and their eyes glaze over.
However, the night sky is dark, and extremely dim light is required to balance the foreground with the night sky. We are talking about quarter moon phase light levels.
I took three Luxli Viola² 5" On-Camera RGBAW LED Lights for this trip. Aside from meeting the just-shared requirements, the battery is powerful and removable, permitting the lights to be checked on a flight. In addition, a Bluetooth controller app enables the lights to be controlled remotely, an especially helpful option when working in challenging areas in the dark.
While the Viola lights are not the lowest wattage lights, they dim to a much lower intensity than the considerably lower wattage lights I've tried, even at their 1% settings (making me question the accuracy of the 1% setting indication). The Violas use the common NP-F550 Lithium-Ion battery pack. This battery is not tiny relative to the light, but it is long-lasting (especially at 1% lighting levels) and readily available.
On this morning, I carried all of the requisite gear to the location — at 2:30 AM. This time of the day, along with strong wind and low temperature, resulted in complete solitude.
Because of the uneven, rocky scenario behind the arch, the plan was to set up the accent light on Robus Monopod supported by a compact Robus SBM-001 Stabilizing Base. That plan seemed great until I returned to the camera position and heard the distinct sound of a Viola light hitting rock.
Remember that wind factor I mentioned? There was not enough base surface area to prevent the light from blowing over. At that time of the night, it took two such occurrences to prove to me that this light stand was insufficient for the conditions.
A true light stand is a inexpensive, lightweight option for positioning low level lights. After all, holding lights is what they are designed for. However, these need a flat surface (or a weight) to prevent them from tipping over.
Tripods provide significantly more flexibility and stability, and there were two tripods in the MindShift Gear BackLight Elite 45L. Hoped for was that I could shoot with two cameras simultaneously, but the reality was that the Really Right Stuff Ascend-14 Long Travel Carbon Fiber Tripod had to take on the light stand role.
Did I tell you about the wind? While hearing the light hit the rocks twice was painful, hearing the new RRS Ascend-14 go down into the rocks provided that sick feeling you've likely experienced at some point in life. But, unwavering to the challenge (and better educated), I improved the Ascend-14 setup, and there were no more blow-downs.
Noteable is that the Viola light suffered only a scratched plastic housing after falling approximately 4' into the rocks three times.
A second light was positioned on a rock far off to the camera left to provide broad foreground lighting.
The next challenge was getting the lights dim enough for the scene. Even at 1% brightness, the Violas required flagging of much (75%?) of their face. While the flagging requirement left this equipment project incomplete, a high-quality, workable solution was in hand.
I enjoyed photographing the Milky Way until the sky became bright enough to hide the stars.
What is the best neutral density filter for night photography? That is a question you have not likely asked before. However, the 1% light output was too bright, and this project was continued upon my return to the studio. Some of the light had to be blocked.
The Viola lights are not the smallest available models, and if the light requires dimming, why not select a smaller, lighter light to work with? Since I was going to block light, perhaps I could block the extra light coming from more compact LED lights.
The second round of research resulted in a few Simorr Vibe P96L RGB Video LED Lights joining the kit. That the Simorr P96L light specs are solid, and their cost is considerably less than the Violas, are positive aspects.
The Simorr batteries are integrated, meaning the light must be carried onto a plane and that a fresh battery cannot be inserted in the field. However, these lights are so small that they require little space in the first place. The battery drain at 1% is low, and a second light costs only a bit more than a spare NP-F550.
Back to the dimming problem. Neutral density filters are designed to block light, and that is the need being addressed.
You care about the spectrum color neutrality of your lens, and we just discussed the need for your light, but the spectrum color neutrality of your neutral density filter is just as important — and perhaps a bigger challenge to overcome. Color deficiencies can be accounted for during post-processing, but accurately fixing the deficiency requires high-level post-processing skills, along with an image of a standard ColorChecker or similar captured in the same lighting. When the spectrum deficiency is not identical throughout the image (the LED light will not affect the sky color), the color correction skill level requirement increases significantly.
The next phase of this project was to order a Lee Filters Zircon Dark Density 24x24" Gel Filter Sheet. Simply cut the inexpensive gel filter into LED light-sized pieces, and tape them on the lights as needed. Right? That plan seemed ideal until the strong red color cast in the test images immediately disqualified this solution.
Knowing that many threaded neutral density filters have the same problem and that there was a resolution, I gaffer taped a Breakthrough Photography neutral density filter, known to be free of color cast, over the Simorr light. The result was perfect.
While carrying a range of round ND filters in the night photography kit to tape on rectangular LED lights is not optimal, this is the best solution I've found so far. Breakthrough's 100mm square neutral density filters align nicely with the size of the larger Viola lights, but they are an expensive addition to a kit not otherwise using them.
Back to the low-level nightscape lighting strategy. Surely, you have heard of light painting. So here are the low-level lighting advantages over light painting.
What are the Low-Level Lighting Advantages Over Light Painting?
What are the Light Painting Advantages Over Low-Level Lighting?
Reviewing the Lights:
What are the Low-Level LED Light Requirements?