Theta Pond Rainbow

hen I did my 2020 In Review video one of the things I mentioned as a goal for 2021 is to do more long exposures, especially with ND filters. Soon afterwards I decided to bite the bullet and get a nice 10-stop ND filter (or, as my wife calls it, a very dark circle) for my 50mm lens and the first thing I wanted to do was go down to the OSU campus and take a picture of the rainbow at Theta Pond.

In the winter when the sun is low on the horizon there’s a good chance of seeing a rainbow in the fountains, but you have to catch it at the right time of day when looking at the fountains from just the right angle. It’s a really cool sight, and not difficult to capture with a camera, but usually you end up with a picture that looks like this:

It’s not bad, but it looks kind of messy with the droplets frozen in midair while the pockmarked surface of the water gives a sense of messiness to the overall composition. When I shot this picture (the one you see directly above) I wanted to create motion trails, but all I could do was lower the ISO to 100 and close the aperture to f/16, but even then the shutter speed was 1/15 second which is nowhere close to long enough if you want to show motion trails in a fountain.

Enter the 10-stop ND Filter!

After getting the filter I raced down to campus with my kids and let them run around while I fiddled with my camera for a while. The result is what you see at the top: a much smoother pond surface, silky-smooth motion trails from the fountain, and a sense of peace and calm that doesn’t exist in the other image. The key difference between the two images is shutter speed: 15 seconds vs 1/15 second. Letting the shutter stay open for so long during a bright afternoon day lets you capture images like this, and I’m thrilled to find out what else I can do with this ND filter in the coming months.