How to Capture Cloud Inversions and Iridescence with a Variable ND

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I’ll take moody fog and interesting cloud formations over bright blue skies any day. Shifting veils of vapour inject intrigue and moodiness into a landscape. Add a variable ND filter to your bag and a whole world of dreamy photography techniques opens up.

Words and Photography by Caitlin Fullam

I take every opportunity to chase clouds and fog in the foothills near my home. Here in the arid high desert landscapes of Colorado, humidity and precipitation are scarce weather events I methodically watch for. My obsession is simple – fog transforms the everyday into something new and mysterious. The way it blankets whole cities, transforms light, and laps at mountainsides like a sea evokes awe like nothing else.

Having recently added the Urth Variable ND8-128 to my photography repertoire, I have been excited to capture interesting cloud phenomena using slower shutter speeds to create dreamy effects.

“Being a landscape photographer means being a part time meteorologist.”

Shot with an Urth Variable ND8-128.

Chasing a sea of clouds

I’ve heard it said that being a landscape photographer means being a part time meteorologist. I’m no expert but I’ve definitely developed an instinct for cloud inversions. 

The conditions you want to look for are high humidity, precipitation leading to clouds overnight, leading to partial sun just after sunrise. High air pressure and low wind are key, so that the clouds can settle. I’ve found valleys and lakes are hot spots for these conditions. 

If the morning seems dark and overcast, try to get up above the clouds, such as by driving up to a mountain lookout until you reach clear sky. Similar to looking out the window of an airplane, you’ll find yourself standing above a vast lake of fluffy candy floss.

It’s helpful to start shooting during blue hour because the lack of light will allow your camera to take even longer shutters.”

I love shooting inversions at sunrise because the beautiful light tints the cloud layer with soft pastels. In order to capture dreamy fog wisps with a variable ND filter, I recommend getting to your location 30 minutes before sunrise, so that you have plenty of time to set up a tripod and dial in your settings. It’s helpful to start shooting during blue hour because the lack of light will allow your camera to take even longer shutters, such as 30 seconds or more.

First I like to shoot without a filter to compose the shot and set focus manually. Then I screw the ND filter on and twist the dial to the darkest setting possible (ND128 in my case) and use a small aperture (f/11-32) to create the longest shutter I can. From there I play with the filter and my camera settings, taking incrementally shorter shutter speed images until I find the settings that are most pleasing to my eye. 

You’ll find that sometimes 30 seconds creates perfect fog wisps, but other times 10 seconds might be preferable. Very long exposures can sometimes blur the fog too much for my taste, so it really depends on what you’re after, as well as the motion of the fog. 

The variable ND allows you to try so many different shutter speeds on for size. It also enables you to continue shooting long exposures well after the sun has risen. 

Fog in other forms

Low clouds and humidity can create other whimsical conditions such as steam fog rising over bodies of water, pogonip fog forming over ice, and hoarfrost – that crunchy crystalline vapour that you’ll see around the edges of leaves, fences, even hair.

Once I’m done shooting a cloud inversion sunrise, I always drive back down into the valley to hunt for these weather gems. If I’m lucky enough to find a pond with steam fog rising, the variable ND comes in handy again as a tool to create long exposures- smoothing out ripples in the water to create glassy reflections. 

Once the sun is out and breaking through the clouds, the variable ND filter at one or two stops helps me shoot towards the sun at a wide aperture without maxing out my shutter speed.

Unexpected iridescence

Sometimes going out to shoot when conditions aren’t ideal means stumbling upon unexpected cloud shows. One bright winter morning I was lucky to witness an optical phenomena known as cloud iridescence, causing the clouds nearest the sun to suddenly erupt in radiating rainbow striations resembling soap bubbles or mother-of-pearl.

As the sun was right below these opalescent clouds, it was impossible to look straight at them for any length of time or shoot them without maxing out my shutter speed. The ND filter was crucial to allowing me to focus on them and capture their radiance.

Get creative

The truth is, even if the weather app predicts perfect clouds conditions, sometimes interesting weather events don’t pan out. That just means you have to get more creative! Bringing along a variable ND and a tripod opens up your options so that you can be playful with the light and weather conditions you’ve got.

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Caitlin Fullam

Caitlin is a travel and outdoor lifestyle photographer living in Boulder, Colorado. She inspires wanderlust and tells stories of awe through creative self portraiture and whimsical dreamscapes.