Cave Photography

I recently went to visit Ruby Falls in Chattanooga, TN. Since this was my first trip, of course I was going to take some photographs.

So how to go about taking pictures in a dark and wet cave when you’re in a tour group and have to keep up with the group? It’s not my first cave trip nor my first photography excursion in a cave. But it was the first since I switched from a DSLR to a mirrorless camera.

My previous cave trips were either with a film camera or various generations of DSLR’s – the latest being a Canon 7D.

With film, you either needed a tripod – which most caves frown upon – or a fast (high ISO) film which had a problem with being very grainy/noisy. In the days before digital imaging and noise reduction software, the pictures from such film were largely unusable due to the grain and motion blur.

With the DSLR, the problems were similar – instead of grain, you have the issue of noise at high ISO settings and trying to balance the noise with motion blur.

Now, with the latest mirrorless cameras with their improved noise performance at high ISO coupled with good noise reduction software you can take decent pictures while touring caves. Here’s what I did on my recent trip.

Using a Canon R7 with an EF-R adapter and a Canon 10mm-22mm f:3.5-4.5 EFS lens, I set the camera to shutter speed priority at about 1/80 second, and ISO setting to Auto. Even so, 80% of the images were taken at ISO 3200 or higher, and about 25% required shutter speeds slower than 1/60 second.

Since the R7 is an APS-C sensor size, the lens gave me an effective full-frame range of 16mm to 35mm. I chose the super wide zoom because I knew there was a waterfall in the cave and wanted to make sure I could get all of it in the frame yet hoping that the top end of the zoom range would be enough to get a good view of the stalactites and other features of the cave.

I set the shutter mode to full electronic to reduce in-camera shake and the highest speed continuous shooting so that I could fire off a burst of several frames in the hopes that at least one of the burst would be reasonably sharp.

I was a little concerned about water dripping onto the camera and lens from overhead and compromising my images, so I just kept it pointing down when not actively using it and I made sure I had a microfiber cloth to dry the lens if I did get some drops or fog on the lens.

For the most part, my plan worked. If I saw something I thought would be image-worthy, I’d stop (or really slow down), fire off a burst of 5 to 10 shots, and then move on. Even though I was taking pictures along the way, I was able to keep up with our guide and group and not keep folks waiting too long for me to catch up. In this way, I took over 500 images on a 1-hour tour and was able to salvage over 100 images to share with my tour mates.

Here’s an extract of one of the images before and after noise reduction with Topaz Denoise AI.

And here is the final image –

And, here are some of the other images –

As far as processing, these were basically just imported into Lightroom, Auto White Balance selected, reduced Highlights by 100 and opened Shadows by 100, then setting the Black and White Point.

In retrospect, the super wide was a benefit for the waterfall, the larger formations and the closer formations. I think a longer focal length for the images of the ceiling would have been better – maybe the 50 mm f:1.8 or possibly even longer focal length. If would mean changing the lens in that damp wet environment, but I think it would have made better images of the higher parts of the cave.