When I first looked into the opening of the Devil’s Ice Box, I wasn’t sure what would happen with a time exposure. There was barely enough light to focus on the rocks–I was lucky that all of the mist above caused by the hot, humid air hitting the cool air from the cave was creating a giant diffuser. Essentially, localized cloudy conditions on a sunny evening. I was surprised at the colors that were revealed in the first time exposure–I started at 30 seconds at ISO 800. I re-adjusted for a bulb exposure at ISO 400 for less noise. You can see this same sliver of stream passing underground through the cave system in the photo below:
I took an excursion–albeit brief–to Rock Bridge Memorial State Park in the early evening hours tonight. A sudden thunderstorm that passed through Columbia this afternoon had left the colors saturated, and the boardwalk to the Devil’s Ice Box (an extensive cave in the park) was slippery. As I turned back to see the way I came–taking a cue from Dewitt Jones’ sappy, but helpful mantra “Look around, Dewitt”–I saw the sun bursting through the tree canopy. Normally, for a scene like this, I wouldn’t worry about stopping down beyond f/9, possibly f/11, but for maximum sunburst without risk of image deterioration due to diffraction, I chose f/16. I prefer to avoid a lens’s minimum aperture–you can test the theory yourself, and you will find that your lens becomes less sharp, not more-so, at its smallest aperture.