Approaching Rain, photo by Harold Davis. View this image larger.

On Sunday we went for a hike on Point Reyes with our friends Mark and Amy. This was a get-away-from-the-kids that we’d been looking forward to, with Rachel prepared to babysit all three boys until whenever we got back.

Unfortunately, the weather was sloppy. By the time we got out to Inverness on the Point Reyes peninsula, the rain was coming down steadily. We had a long lunch, and by the time lunch was over it looked like the rain was letting up.

What was a little rain, anyway? We decided to go for our hike even in the wet weather. Luckily, by the time we reached the trailhead parking lot for the Estero Trail, the rain had stopped completely.

We had a nice hike, with some good photo opportunities. By the time we got back to the parking lot it was dark. This was my last photo of the day, taken in almost complete night. As I released the shutter, a few drops of rain had started to fall. By the time I packed camera and tripod up, and ran to the parking lot, cold rain was coming down hard.

If you look at the Exif data for this image, you can verify for yourself that this was a long exposure, thirty seconds, with the 10.5mm digital fisheye lens wide open at f/2.8. But it really doesn’t look like a long exposure in almost complete darkness should look. In fact, I bet if you were shown this photo and didn’t know any better, you would think it was taken in the daytime, perhaps the late afternoon (with the incoming storm).

In cinematography, there’s a technique called Day for night, which uses lighting and filtration to make a scene shot during the day appear to take place at night. The effect shown in this image, of converting night to apparent day, strikes me as a kind of opposite Night for Day (hence the title of this story).

The fact is that digital sensors are far more sensitive to light beyond the visible spectrum than we are (and far more so than film). Do long exposures when IR and UV radiation is bouncing around, and weird things start to happen as in the image that illustrates this story, this moonlight vista of the Golden Gate, and this photo by star light in the High Sierras.

Related story: Xrays, Photograms, and Cross-Processing, Oh My!