Eloquent Images by Gary Hart
Insight, information, and inspiration for the inquisitive nature photographer
An Old Friend Returns
Posted on May 22, 2026
Moonlight Prism, Lower Yosemite Fall Moonbow, Yosemite
Sony α1
Sony 14mm f/1.8 GM
ISO 1600
f/1.8
4 seconds
Has anyone noticed that Yosemite becomes a completely different park with each season? I feel quite fortunate to live close enough that I’m able to enjoy each Yosemite season, and to offer Yosemite workshops in three of four seasons. (Actually, you can probably infer that I live close enough to offer workshops in all four seasons, but I leave summer to the tourists.)
Each Yosemite season offers its own distinguishing qualities. In autumn, though the falls are nearly dry (Bridalveil still trickles), red and gold leaves fill the trees, carpet the ground, and reflect gloriously in the low and slow Merced River. Winter is when the waterfalls return to life, and also the best time to find Yosemite draped in powdery white—but since snow is never guaranteed, I always schedule a workshop around the natural firefall light on Horsetail Fall (while still crossing my fingers for snow). Spring is the Yosemite of postcards and calendars, when waterfalls peak, dogwood blooms abound, low-lying meadows host (reflective) vernal pools, and rainbows color the waterfalls.
Each of these Yosemite workshops has a potential bonus lunar event that I try to include when it corresponds with the season’s primary distinguishing quality. Many autumns and winters I can align a rising full moon with Half Dome at sunset, and spring is when the light of a full moon paints a rainbow at the base of Lower Yosemite Fall.
For years I scheduled two workshops around this moonbow, but finally decided that the window for the absolute best moonbow experience is open only during a four week span from early April into early May. Though a moonbow also happens with the full moon from late March and into June, in late March and early April the moonbow appears in the mist billowing too far left of the fall; later in May and into June, the crowds swarming Yosemite Valley make an unpleasant experience for everyone.
Despite the remarkably predictable moon/landscape geometry that creates a moonbow, its appearance is never certain. Clouds are the biggest nemesis, but low water can also diminish the experience. Coming into this year, limiting my moonbow workshops to a single full moon in that four-week window, combined with factors beyond my control (in addition to clouds, you can add a sudden park closure and global pandemic), has meant that my previous successful moonbow sighting was in 2019. And for a while, it appeared 2026 would continue that streak of futility.
There was a time when I didn’t believe it possible for Yosemite’s spring runoff to be so low that the moonbow would essentially be erased. But as California’s wet season progressed and the Sierra Nevada range found itself on the way to an historically poor snowpack year, I couldn’t help flashing back to 2015. That’s the year PBS Newshour arranged for a film crew to follow me and my Yosemite spring workshop group as we photographed Yosemite’s spring splendor, with a particular emphasis on the moonbow. But 2015 also happened to be the year an unprecedented drought shrunk Yosemite’s normally booming spring waterfalls to mere trickles. Rather than cancel the Newshour segment and keep the film crew home, they adroitly pivoted to a piece on California’s drought and its impact on Yosemite. Check it out. (FYI, I haven’t aged a bit since then.)
Would history repeat this year? As April approached, the answer appeared to be yes. Then a series of unseasonably cold storms arrived, filling our rivers and bolstering the Sierra snowpack just in the nick of time. A couple of days before the workshop (scheduled for the last four days of April), another storm landed, further recharging the falls and even lingering through the workshop’s first couple of days—just enough rain and clouds to provide excellent photography, but not enough to wash us out. Suddenly, my concern wasn’t that there would be enough water, it was whether the clouds would depart in time for my planned Wednesday night moonbow shoot.
Even with all this last-minute moisture, spring 2026 was not especially wet in Yosemite. Though still flowing beautifully, all the falls were noticeably on the low side of average for this time of year (peak runoff is usually around May 1). Nevertheless, there was more than enough water exploding on the rocks beneath the falls to form the billowing mist Yosemite’s signature waterfall rainbows require.
Throughout the workshop my group enjoyed an assortment of daylight rainbows, from various vantage points (I have the timing down to the minute for each location, creating the illusion that I’m much smart than I am), but it was the moonbow everyone was crossing their fingers for. I had one person in the group who had already taken this workshop twice, each time with the expressed desire to photograph the moonbow. With Kent was returning for a third attempt, the pressure was on and I was pretty committed to making it happen for him if at all possible.
Since the moonlight timing and angle would be best on Wednesday, the workshop’s penultimate night, I tried to get everyone up to speed on moonlight and moonbow photography during that afternoon’s training session. The evening’s sunset shoot featured the full moon rising over Bridalveil Fall, photographed from an elevated turnout on Big Oak Flat Road. As soon as we finished there, I zipped the group back down to the Yosemite Valley Lodge parking lot, where we grabbed our gear and made the short walk, in the gathering dark, up to the bridge at the base of Lower Yosemite Fall.
The below average flow in the fall meant that this year’s moonbow wouldn’t be as big, or last as long, as it does in the wettest years. That’s because less water means a smaller cloud of mist for the bow to form in, not only shrinking the moonbow’s breadth, but also terminating the show sooner, as the rising moon shifts the necessary 42 degree rainbow angle downward and eventually out of the mist. (Rainbows drop as the sun or moon rises—read more about the geometry of rainbows on my blog) But this year’s moonbow was plenty big enough to thrill everyone, providing about 40 minutes of quality photography between the time the sky was dark enough for the moonbow to appear, and when it dropped out of the mist.
Even with less water than usual, the moonbow was obvious to the unaided eye as a shimmering silver band. And the rainbow colors were clearly visible in our mirrorless viewfinders or live-view LCD screens, even before a picture was captured.
The diminished flow in Yosemite Fall had one major advantage: at no point did we feel like we were photographing in a rainstorm. Every once in a while we’d get sprinkled with a small amount of mist, but I’ve photographed the moonbow from here when everyone had to don rain gear, and even a single 5-second exposure—that started with a dry lens—would finish with the front lens element completely misted over. When it gets like this, the only way to do it is with an umbrella in one hand and a towel in the other.
There were quite a few people the bridge this evening, but I’ve seen far more here. We’d become a little scattered on the walk up to the fall, so it took me a little while in the darkness to ensure everyone in my group had found a suitable spot to set up. Once I was confident my group was positioned satisfactorily, I tried to get around to everyone to make sure they were doing okay.
Exposure for the moonbow is pretty easy, and I’d given them settings to use before we started. Composition is a little tougher given the limited light, but I’d very strongly encouraged everyone to put their lens at its widest focal length and leave it there—this simplifies things, and today’s digital cameras have more than enough resolution to allow ample cropping later.
Not only does shooting wide streamline composition in the dark, it simplifies the most challenging aspect of night photography: focus. Since changing focal length requires refocusing, and finding focus in the dark is not easy, once you’ve achieved sharpness you don’t want to do it again. Most of my time this evening was spent moving around between the members of my group, helping them get focused, or checking their focus to make sure it was good. I started with Kent, but eventually made it around to nearly everyone (and even helped one or two people who weren’t in my group).
Eventually I found a few minutes for some frames of my own, squeezing in between a member of my group and another person who was okay with me and my tripod up in his space (I checked). I take both horizontal and vertical versions of virtually every scene I photograph, but I always photograph the moonbow vertically because I just haven’t found a horizontal composition that pleases me. For starters, I want to include as much sky as possible, and I think Yosemite Creek churning through granite boulders is a far more interesting than the trees on the left and right. This evening, I used my 14mm prime lens, enabling me to include a lot of starry sky above the fall (including 5/7 of the Big Dipper), while still getting plenty of moonlit creek and granite beneath it.
You can tell that I captured this toward the of the moonbow window by how low the moonbow is. When we arrived, it hovered above the visible mist, just below the top of the lower section (where the fall starts to spread). So even though my moonbow is not quite as broad as the earlier ones, it is brighter, thanks to all that water.
I should probably add a few words about my exposure. I started doing moonlight photography about 20 years ago, and established my full moonlight exposure values very early on. Back then, then ISO 400 was about as high as I could go without noticeable noise; since my fastest lens at the beginning of my digital years was f/4, so my exposure settings were usually in the ballpark of ISO 400, f/4, 30 seconds.
The problem with 30 seconds is you get a little star movement—not a deal-breaker, but enough to be visible if you look closely. So as sensor technology improved, and I acquired faster lenses, my ISOs went up and my shutter speeds dropped, while my exposure values (amount of light captured) remained constant. For this one, I used f/1.8, ISO 1600, and 5 seconds.
With limited time, and even more limited ability to move around, I still managed to get a handful of frames this night. But that was fine because my photography is never the priority in a workshop (and I certainly don’t lack for moonbow images from past years). Even though this year’s version may not be my best moonbow shot ever, I’m still pretty pleased with my results.
In the image review the next day, I invited everyone to share a moonbow image in addition to their review image—it was wonderful to see that everyone had a success! That includes Kent, who had to leave the workshop early, but who reported to me that his moonbow image is beautiful and he’ll no longer need to repeat the course.
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Yosemite Falls, Day and Night
Moonlight Magic
Posted on May 12, 2020
Moonbow and Big Dipper, Lower Yosemite Fall, Yosemite
Canon EOS-1Ds Mark III
22 mm
30 seconds
F/4
ISO 800
Rainbows demystified
A rainbow forms when sunlight strikes airborne water droplets and is separated into its component spectral colors by characteristics of the water. The separated light is reflected back to our eyes when it strikes the backside of the droplets: Voila—a rainbow!
There’s nothing random about a rainbow—despite their seemingly random advent and location in the sky, rainbows follow very specific rules of nature. Draw an imaginary line from the sun, through the back of your head and exiting between your eyes—when there are airborne water droplets to catch that light, a will rainbow form a full circle at 42 degrees surrounding that line (this won’t be on the test). Normally, because the horizon (almost always) gets in the way, we see no more than half of the rainbow’s circle (otherwise it might be called a “raincircle”). The lower the sun is, the more of the rainbow’s circle we see and the higher in the sky the rainbow extends; when the sun is higher than 42 degrees (assuming a flat horizon), we don’t see the rainbow at all unless we’re at a vantage point that allows us to look down (for example, looking into the Grand Canyon from the rim).
Read more about rainbows on my Photo Tips Rainbows Demystified page.
Moonbows
Moonlight is nothing more than reflected sunlight—like all reflections, moonlight is a dimmer version its source (the sun). So it stands to reason that moonlight would cause a less bright rainbow under the same conditions that sunlight causes a rainbow. So why have so few people heard of lunar rainbows (a.k.a., moonbows)? I thought you’d never ask.
Color vision isn’t nearly as important to human survival in the wild as our ability to see shapes, so we evolved to bias shape over color in low-light conditions. In other words, colorful moonbows have been there all along, we just haven’t be able to see them because they’re not bright enough. But cameras, with their ability to dial up sensitivity to light (high ISO) and accumulate light (long exposures), “see” much better in low light than you and I do.
While it’s entirely possible for a moonbow to form when moonlight strikes rain, the vast majority of moonbow photographs are waterfall-based. I suspect that’s because waterfall moonbows are so predictable—unlike a sunlight rainbow, which doesn’t require any special photo gear (a smartphone snap will do it), capturing a lunar rainbow requires at the very least enough foresight to carry a tripod, and enough knowledge to know where to look.
Nevertheless, even though we can’t see a moonbow’s color with the unaided eye, it’s not completely invisible. In fact, even without color, there’s nothing at all subtle about a bright moonbow—it may not jump out at you the way a sunlight rainbow does, but if you know where to look, you can’t miss a moonbow’s shimmering silvery band arcing across the water source.
Yosemite Falls moonbow
Despite frequent claims to the contrary, moonbows can be seen on many, many waterfalls. Among the more heralded moonbow waterfalls are Victoria Falls in Africa, Cumberland Fall in Kentucky, and (of course) Yosemite Falls in Yosemite National Park.
Yosemite Falls is separated into three connected components: Upper Yosemite Fall plummets about 1400 feet from the north rim of Yosemite Valley; the middle section is a series of cascades dropping more than 600 feet to connect the upper and lower falls; Lower Yosemite Fall drops over 300 feet to the valley floor. While there are many locations from which to photograph the moonbow on Upper Yosemite Fall, the most popular spot to photograph it is from the bridge at the base of Lower Yosemite Fall.
The Lower Yosemite Fall moonbow is not a secret. Arrive at the bridge shortly after sunset on a full moon night in April, May, and (often, if the fall is still going strong) June, and you’ll find yourself in an atmosphere of tailgate-party-like reverie. By all means come with your camera, tripod, and rain gear, but don’t get so caught up in the photography that you fail to appreciate the majesty of this natural wonder.
Following a typical winter, in spring the mist and wind (the fall generates its own wind) on and near the bridge will drench revelers and cameras alike. After a particularly wet winter, the airborne water and long exposures can completely obscure your lens’s view during the necessarily long exposures. And if the wet conditions aren’t enough, if you can find a suitable vantage point, expect to find yourself constantly jostled by a densely packed contingent of photographers and gawkers stumbling about in limited light. Oh yeah, and then there are the frequent flashes and flashlights that will inevitably intrude upon your long exposures. But despite all these challenges, I’ve done this long enough to know that success is very possible if you know what you’re doing.
If, knowing all that, you still have visions of a moonbow image, it’s best to come prepared:
- A tripod and digital SLR camera are must (a film camera will work too, but it adds complications I won’t get into here)
- Wear head-to-toe rain gear so you can concentrate on keeping your camera dry
- Bring a chamois or towel—you’ll be using it frequently
- An umbrella can help keep water off your lens during a long exposure
- Practice moonlight photography (you’ll find my how-to of moonlight photography, including exposure settings and focus techniques, in the link) before you get there—trust me when I say that you don’t want to be learning how to photograph by moonlight while you’re trying to capture a moonbow in a mosh pit.
- Don’t have time to practice before your visit? Stop at the top of the Lower Yosemite Falls trail, where you can see the entire fall from top-to-bottom, and practice there—you won’t see a moonbow (the angle is wrong), but the conditions are much easier, and these might just turn out to be your favorite images of the night.
About this image
I’d taken my May workshop group to Glacier Point on this night, so we didn’t arrive at Yosemite Falls until nearly an hour after the moonbow started. This late arrival was intentional because California’s severe drought has severely curtailed the mist at the base of the lower fall. In a normal year the mist rises so high that the moonbow starts when the moon is quite low (remember, the lower the sun or moon, the higher the bow); this year, I knew that the best moonbow wouldn’t appear until the moon rose and the bow dropped into the heaviest mist. Not only that, the later it gets, the few people there are to deal with.
I’d given the group a talk on moonlight photography that afternoon, but we stopped at the top of the trail to practice for about 20 minutes, using the exquisite, tree-framed view of the entire fall. When everyone had had success, we took the short walk up to the bridge and got to work.
We found conditions that night were remarkably manageable—by the time we arrived at the bridge, at around 9:45, the crowd had thinned, and our dry winter meant virtually no mist on the bridge to contend with. I started with couple of frames to get more precise exposure values to share with the group (moonlight exposures can vary by a stop or so, based on the fullness of the moon, its size that month, and atmospheric conditions), then spent most of my time assisting and negotiating locations for my group to shoot (basically, wedging my tripod into an opening then inviting someone in the group to take my spot).
This image is one of my early test exposures—I went just wide enough to include the Big Dipper (just because it’s a test doesn’t mean I’ll ignore my composition). In wetter years I’ve captured move vivid double moonbows and complete arcs that stretch all the way across the frame, but I kind of like the simplicity of this image, and the fact that I was able to include the Big Dipper, which appears to be pouring in the the fall.
Chase the Moonbow With Me in April
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Moonlight Magic
Yosemite Spring
Posted on April 21, 2019
Moonbow, Lower Yosemite Fall, Yosemite
Sony a7RIII
Sony 12-24 f/4 G
10 seconds
F/4
ISO 1600
There are many (many!) beautiful sights in Yosemite, but when most people think about Yosemite, they think about waterfalls and granite. The granite is forever (virtually), but Yosemite’s waterfalls come and go with the season: exploding from the granite walls in spring, most of Yosemite’s waterfalls are bone dry by summer’s end. And some years are better than others—three springs ago, Bridalveil and Yosemite Falls were barely a trickle, too dry to photograph (unprecedented in my lifetime). The next spring the deafening roar of waterfalls was back, echoing throughout Yosemite Valley.
Moonbow, April 18, 2019
I just returned from my annual Yosemite Moonbow and Dogwood photo workshop on Friday night (technically, it was early Saturday morning). The dogwood are just starting to pop, but the waterfalls are going strong, with enough snow in the high Sierra bank to keep them roaring through summer.
My group photographed more waterfall rainbows than I could count, on both Bridalveil and Yosemite Falls, but the highlight was Thursday night’s lunar rainbow (moonbow) shoot on the bridge beneath Lower Yosemite Fall. Nothing compares to the first time seeing a moonbow. A shimmering silver arc, a moonbow is clearly visible to the naked eye—proper exposure in a camera reveals the moonbow’s vivid color.
A “practice” moonlight shoot the previous night helped prepare everyone for the difficulties of photographing in the dark. And while my group came prepared for moonlight photography, the crowds and mist make things difficult even for the seasoned veteran. The crowds weren’t too bad this year, but while lots of water in the fall means a better moonbow, it also means a wetter photographer.
I feared that the thin cloud cover that had delivered a spectacular sunset just as the full moon rose just an hour or so earlier, would douse the moonlight necessary for a moonbow, but that turned out to be a non-factor. One problem was contrails, more than I’ve ever seen. Some chose to leave the sky (or most of the sky) out of their frame; I opted to include the sky, then carefully execute a contrailecotmy in Photoshop.
Because most of my time on the bridge is spent assisting the group, I only got to click a handful of frames. I started on the (drier) paved open area before the bridge, but after working with a workshop participant on the bridge, I decided the view there was worth getting wet.
I went wider with this year’s images than previous years, using my Sony 12-24 G lens on my Sony a7RIII camera. I focused on the moon, then turned around and set up my composition. Concerned about too much water on my front lens element, I bumped my ISO to 1600 to keep my shutter speed at 10 seconds or faster. When I was ready to click, I wiped down the front of my lens with a towel that I lifted just as my shutter clicked.
Yosemite April 2019 Images
(processed so far)
Shameless plug
I just scheduled my 2020 Yosemite Spring photo workshops, April 5-8 and May 4-7. Both are timed for the full moon to maximize our moonbow chances. And of course it’s not all about waterfalls and rainbows—this year’s spring workshops included some spectacular clearing storms, beautiful moonrises, and brilliant poppies. In addition to great photography, you’ll improve your photo skills with daily training and image reviews. You’ll also have lots of fun.
Yosemite Spring
Click an image for a closer look and to view slide show.
Yosemite Moonbow
Posted on April 6, 2018
Moonbow and Big Dipper, Lower Yosemite Fall, Yosemite
Canon EOS 1DS Mark III
Canon 17-40 f/4L
30 seconds
F/4
ISO 800
Even though your spellcheck says it doesn’t exist, I promise you that a moonbow is a very real thing indeed (and I have the pictures to prove it). Some argue that “lunar rainbow” is more the technically correct designation, but since that moniker just doesn’t convey the visual magic, I’m sticking with moonbow.
This won’t be on the test
Because a moonbow is a rainbow, all the natural laws governing a rainbow apply. But all the moonbow’s physics can be summarized to:
1) Your shadow always points toward the center of the moonbow (put your back to the moon and note the direction your shadow points)
2) The higher the moon, the lower the moonbow and the less of it you’ll see
3) When the moon is above 42 degrees (assuming flat terrain), the moonbow disappears below the horizon
Yosemite’s moonbow
Each spring, Sierra snowmelt surges into Yosemite Creek, racing downhill and plunging 2,500 feet in three mist-churning steps as Yosemite Falls. Shortly after sunset on spring full moon nights, light from the rising moon catches the mist, which separates and bends it into a shimmering arc. John Muir called this phenomenon a “mist bow,” but it’s more commonly known today as a moonbow.
While a bright moonbow is visible to the naked eye as a shimmering silver band, it isn’t bright enough for the human eye to register color. But thanks to camera’s ability to accumulate light, the moonbow’s vivid color shines in a photograph.
I just returned from the first of two moonbow workshops scheduled for this spring, but haven’t had time to process this year’s moonbow images. The above image was captured a few years ago near the bridge at the base of Lower Yosemite Fall. Not only was it crowded (the moonbow is no longer much of a secret), wind and mist made the necessary 20- to 30-second exposures an exercise in persistence. Not only was I able to capture the moonbow, as you can see, I now have photographic proof that the Big Dipper is the true source of Yosemite Falls.
A Moonbow Gallery
Click any image to scroll through the gallery LARGE
Eloquent Images by Gary Hart 