|
||
The constellation of Orion rises over a light fog on the Mullica River in the Pine Barrens of New Jersey. Driving back from an observing session one night, I ran across this scene. It was spectacular, but I kept driving. I thought "Orion is a little bit too high, I'll come back tomorrow night when it's lower and shoot it. It will be perfect then." And besides, I didn't really have a proper tripod, all I had is a six inch high mini-tripod buried somewhere under all of my packed equipment stuffed into the back of the Jeep. And there wasn't really anyplace to park along the side of the road so I could put the mini-tripod on the hood of the Jeep to shoot Orion lined up just right above the house that was lit up on the other side of the river. And I was tired from an all night astrophotography session. And I'm basically lazy. I had a million reasons not to go to the trouble of shooting this image. But I've learned that when you see a picture like this, you better stop and take it, because it's never there when you go back, or something will be different and it won't be as good. So a couple of miles later, I turned around. I had to park a ways down the road because at this particular vantage point the river was right next to the road, so I couldn't put the mini-tripod on the hood of the Jeep. This meant I had to put it on the ground for the time exposure which I knew would be 15 or 30 seconds. There was a guard rail on the side of the road, so I couldn't lay on the asphalt to frame it, and although I'm crazy and it was 3:30 in the morning, I probably wouldn't have laid in the road anyway. So I had to climb over the guard rail and lay down in the weeds on a 3-foot wide embankment that went down to the river. That was a lot of fun. I didn't know what I was laying in, but I hoped it wasn't ants, and I hoped I wouldn't be covered with ticks (nasty little insects that carry Lyme disease here) when I got up. I knew that the dynamic range of the scene, the range of brightness between the sky and the brightly illuminated house of the river, could probably not be captured in a single exposure. So I made a series of exposures at f/2.8 starting at 1 second, and then increasing by one stop until I got to 30 seconds, the longest shutter speed on the camera. I could have used the bulb setting to go longer, but I knew that even with a wide angle lens, the stars would trail too much if I went much longer than 30 seconds. Indeed, although it is not apparent in this low resolution image, the stars are trailed a bit in the image. The 30-second exposure for the sky was good. It recorded a lot of stars, as well as some brightness and color in the sky, so the sky was not pitch black. It turned out that a 2-second exposure was good for the house on the river. All of the images were shot in the Canon RAW CR2 format. This allowed manipulation of parameters such as white balance, contrast, and to a degree, exposure, to produce an optimum image. However, except for changing the white balance from Auto to Tungsten, little manipulation was done to the raw file except opening it in 16 bits of tonal depth. The JPEG images shot concurrently with the RAW files would have been perfectly fine to use since little tonal stretching was used that would have required the extra bit depth. The Tungsten white balance worked perfectly for the lights on the house on the river, as well as correcting the red/brown color of the sky. Most images taken here in New Jersey suffer from light pollution, causing the sky to be recorded as red/brown in the image. Both images were opened in Photoshop and a layer mask was used to composite the short exposure into the long exposure. Some people might question the "ethics" of compositing two different exposures together, saying that the image is a fake because it wasn't done in a single exposure. However, this method produced a final image that was actually more faithful to the true visual appearance of the scene than a single exposure. Because the human eye is capable of handling a much larger brightness range than a film or digital camera, I could see detail in both the house on the river as well as the stars in the sky, both at the same time as I stood there and viewed the scene. A single camera exposure would not have been accurate. This image is an excellent example of astrophotography that can be done with a simple camera-on-a-tripod setup and a time exposure. You don't need a fancy telescope or tracking mount to take astrophotos! Exposure Data
|