Lower Yosemite Falls Moonbow

February 29, 2020  •  Leave a Comment

Yosemite Moonbow 2 - HRYosemite Moonbow 2 - HRYosemite National Park, CA. The moonbow, which is a rainbow created by the light of a full, or near full, moon is only visible during a short window from mid-April through May. This year's moonbow was remarkable for the significant volume of the waterfall generated by a very high snowpack that had begun to melt. Capturing this amazing scene was further complicated by the strong winds and mist created by the waterfall as it thundered down.

Field Notes: Canon 7D Mark II, EF16-35mm f/2.8L lens at 20mm, 13 sec @ f/2.8, ISO 2000

Overview

During the months of April, May and June a moonbow, also called a lunar rainbow, can be seen in the mist at the bottom of Lower Yosemite Falls. A moonbow is simply a rainbow that occurs using moonlight rather than sunlight. Therefore, a moonbow is only visible when there’s enough moonlight to create the effect, which is typically when the moon is full and a couple of nights before and after. The moonbow can only be seen during the month of April through June because the position of the moon and it’s angle to the falls is aligned to create the effect.

The moonbow is most often photographed from the footbridge on the Lower Falls Trail where it crosses Yosemite Creek at the base of Lower Yosemite Falls. Although, there are locations in Cooks Meadow where the moonbow can be seen from a distance. A moonbow across the Upper Yosemite Falls can also be photographed from around Sentinel Bridge on the south side of Cooks Meadow.

 

Field Info

 GPS Coordinates  37.75039, -119.59667
 Rating  4 - highly scenic
 Difficulty  Easy
 Time of Day  Night
 Dates/Seasons  April - June
 Trailhead Coordinates  37.74603, -119.59621
 Distance & Time  0.35 mi / 15-20 min
 Elevation Change  30' / (50')
 Type of Route  Out-and-Back
 Comments  Full or nearly full moon

 

Directions

The trailhead is across Northside Drive from the Yosemite Lodge where there is parking. It is also an easy 0.2 mile walk along a paved trail from the Cooks Meadow shuttle bus stop. The Lower Falls Trail begins in a paved circular clearing next to the restrooms that has a clear view of the Upper and Lower Falls. Hike north on the trail through the grove of trees for 0.3 miles until you reach the footbridge. There is a clearing to the west of the footbridge surrounded by trees and large boulders that provides some measure of protection from the wind and spray from the falls. There are several wood benches that can be useful for preparing your camera.

When you are finished photographing, the easiest way back is to retrace the route to the trailhead. However, you can also opt to continue east on the Lower Falls Trail which loops around for 0.6 mi back to the trailhead with several spur trails that enable you to reach Cooks Meadow, Yosemite Village and the parking area.

 

Waypoint Dist Elev Comments
1- Lower Falls Trailhead 0.0 3,990' Across from Yosemite Lodge
2 - Old Forest Grove 0.1 4,000' Grove of old growth pine, cedar and hickory trees that offer photographic opportunities
3 - Footbridge 0.35 4,016' Moonbow viewpoint from bridge

 

Composition Considerations

Photographing the moonbow requires certain environmental conditions and camera preparations. It’s also helpful to understand that a moonbow looks different to the human eye than a normal rainbow. The human eye is not as sensitive to low light conditions, which causes the moonbow to be a dull white or almost gray arc. Our eyes are not sensitive enough to discern the colors within the rainbow since the moon’s light output is substantially less than sunlight. However, modern camera sensors are much more capable of vividly capturing the colors within the moonbow.

As with rainbows, there’s several conditions that are needed for the moonbow to appear:

1. The moon must be full or nearly full. Usually 2-3 days before and after the full moon may provide enough light. Although you will generally find the 2-3 day after the full moon is best because the timing of the moonrise occurs after sunset and you'll have a better chance of strong moonlight to create the moonbow before it rises too high in the sky. 

2. It must be dark, so moonrise times are important to ensure the moon is high enough in the sky and at the appropriate angle between 40-42 degrees for the moonbow to appear. Any lower or higher angle and the moonbow will disappear, which is why this phenomenon only lasts for a short while. There are a lot of tall trees between the moon and the falls, so you’ll notice the moonbow fading in-and-out as the moon rises behind the trees and finally above them.

3. The sky must be clear enough that clouds do not block the moonlight.

The quality of the moonbow may also be affected by the amount of mist and spray generated by the falls. The more spray & mist, the stronger the moonbow is likely to be. Fortunately, April to June is the peak period for Yosemite Falls as snow melt adds volume to the waterfall.

 

Be Prepared for Adverse Conditions

It is important to appropriately prepare for the conditions. Assuming the weather is cooperative, pay attention to the overnight temperatures and layer up as needed. The temperature around the falls is usually colder than elsewhere as all of the moisture in the air tends to cool the ambient temperature. Rain gear is essential since the falls generates a tremendous amount of mist and wind. It’s common to have very strong gusts of wind blowing across the footbridge simply from the force of the water falling into the basin at the bottom. The basin is u-shaped, which means the wind created by the force of the falling water has only one place to go - straight out across the footbridge! So, rain gear, a warm cap and waterproof gloves will help keep you warm and dry.

It will be wet on the footbridge, so cover your camera with a rain jacket and affix the lens hood. There’s plenty of room next to the footbridge where it’s sheltered from the mist to setup your camera and tripod. A sturdy tripod is a must - the wind will buffet the tripod and create vibrations on the bridge. I’ve seen people with small lightweight tripods get quickly blown over by the wind. You may need to hold down even a sturdy tripod. Some photographers bring bungee cords or straps to tie their tripod to the wood railing of the bridge to prevent it from accidentally blowing over.

 

Set Your Camera Settings in Advance

Before you setup on the bridge you should set your camera settings in advance to minimize fumbling around with wet fingers. There’s a few different compositions you can setup in advance. Its common to see photographers moving back-and-forth off the bridge to set different composition settings in the sheltered area. Many photographs are taken with a wide-angle focal length, often 16-24mm if you want to capture the entire scene using a portrait orientation. The differences in focal length mostly determine whether or not some of the sky and stars and how much of the rushing water in the creek are in the frame.

A general starting point for exposure settings are 13-15 seconds at f/2.8 or f/4 (depending upon the maximum aperture of your lens) and ISO around 1600. Depending upon the low light sensitivity of your camera sensor, you may be able to push the ISO higher to reduce the exposure time, but my experience has been that ISO settings greater than 1600 are often too noisy to acceptably process. But, if your camera has good ISO sensitivity you may want to try pushing the limits. There’s also some terrific digital post-processing denoise software now available. I use Topax DeNoise AI and have had excellent results, even with very high ISO captures. DxO PhotoLab 2 also has an excellent denoise program.

It is crucial that you set the infinity location on the lens or lenses you plan to use. While the LCD screen and live view can be used to set the focus, you’ll find that the wind and mist will make this challenging. Having infinity properly dialed-in before you step on to the bridge will simplify the capture process.

 

Capturing the Images

So, now you’re layered up, the camera is ready for wet weather and the exposure settings are set. Before you step out onto the bridge make sure your lens cap is on. You should keep a couple of cloths in your pockets. I have found two cloths are needed. One cloth is a larger highly absorbent micro-fiber I use to wipe water off the lens. I also use this cloth to cover the lens if I need to. The second cloth, which I keep in a separate pocket, is used to wipe droplets off the lens and ensure it is clean and clear.  When you are ready to take the photo, remove the lens cap and trip the shutter.

Try to time the capture with a lull in the wind and mist to minimize how much water falls on the lens. You’ll quickly find the process becomes a cycle of: remove lens cap, trip the shutter, wipe the lens, replace the cap, check the LCD live view. Repeat several times. After you have a handful of captures, remove the camera from the tripod and retreat to the sheltered area to wipe down the camera again (I usually bring a few extra towels for this) and review the images. It’s important that you take a moment and increase the magnification on the LCD screen to at least 1:1 if not 2:1 to see if the image is fatally marred by water droplets. My experience has been that only about 30-40% of my captures have an acceptably minimal number of water droplets (you can fix these in post-processing the same way you heal dust spots).

This cycle is basically the process I follow for the 60-90 minutes I’m photographing the scene. I recommend that you use the time to capture different focal lengths and exposure times. Generally, the captures should look overexposed on the LCD. Check the histogram periodically to ensure you’re not blowing out the highlights, which is remarkably easy to do on the moonbow itself and on the falls. This is a highly contrasted scene, so if conditions are nominal you can try bracketing the photos and blending them in post-processing.

Yosemite Moonbow 1 - HRYosemite Moonbow 1 - HRYosemite National Park, CA. The moonbow, which is a rainbow created by the light of a full, or near full, moon is only visible during a short window from mid-April through May. This year's moonbow was remarkable for the significant volume of the waterfall generated by a very high snowpack that had begun to melt. Capturing this amazing scene was further complicated by the strong winds and mist created by the waterfall as it thundered down.

Field Notes: Canon 7D Mark II, EF16-35mm f/2.8L lens at 24mm, 30 sec @ f/2.8, ISO 800

 

Digital Darkroom Considerations

If you do an image search on Yosemite moonbow photographs you’ll see a huge number of images, which may be helpful as you pre-visualize how you want to capture your own image. A perspective I would offer up for some consideration is that I’ve noticed many, if not most, photographs are way too bright and overexposed. While digital cameras are wonderful for capturing light and colors beyond what our human eyes perceive, I think many photographers take that too literally and end up with photographs that look like they were captured in broad daylight with a weirdly blue sky that has stars in it. The reality is that the falls are dark at night, but with interesting light patterns from the moon projected onto the rock wall and the highlights on the cascades of Yosemite Creek below the falls.

My image at the top attempts to balance the reality of the scene with its moody darkness and patterned moonlight which emphasizes that this is a night scene while taking advantage of the colors in the moonbow that the human eye is not able to discern. The artistry comes in revealing the moonbow’s color while realism establishes the context of a moody nighttime scene.

As you prepare to photograph this remarkable natural phenomenon, you may want to visit www.yosemitemoonbow.com which is a website maintained by photographer Brian Hawkins dedicated to the moonbow. Every year he actually goes through the effort to calculate the prime dates and times to photograph the moonbow. And his site offers detailed helpful information about the moonbow and his own perspective on photographing it.

 

Be an outsider, go on a hike!

 

 


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