Aiming for the Stars

I don’t mean to abuse that old cliché. I’m actually referring to the act of pointing a camera at the stars. I’ve been interested in shooting the stars for some time (not the Hollywood variety) but did nothing about it until recently. Then in mid-November, I joined up with a small group of photographers for a night workshop in the desert of southeast Utah. Alas, our early expectations were quickly marred by bad weather. The day after we arrived, the region was hit by two consecutive storm systems that dumped rain, sleet, and snow on the desert floor for nearly five days.

In the face of bad weather, several of us decided to extend our stay and wait out the storm. That decision paid off because the sky finally cleared on day five, and we were able to enjoy a few glorious days under the stars. We photographed both star points and star trails. Star points are short exposures that capture the stars and constellations more or less as they appear to the naked eye. Star trails, on the other hand, are very long exposures that record the rotation of the earth.

Southeast Utah is one of the best places in the country for star gazing. On a clear night in autumn, the desert sky dazzles the senses with a primal display that excites and humbles at the same instant.

There’s something profound about being in the dark, under an umbrella of a billion stars, standing on a salt bed deposited 300 million years ago, and with no noise except for the occasional click of a camera shutter. For those of us who have done it, it is a profound experience indeed. And one that I hope to repeat.

Star photography involves being at the right place under the right sky, an SLR-grade camera mounted on a solid tripod, a good grasp of night photography techniques, a childlike willingness to experiment, and a big bucket of patience. But when these elements happen to converge, magic happens and a serious photographer can turn into an excitable child. At least I did.

You may be wondering why the sandstone arch in the included photos appears so bright. That’s because we “painted” it with light — flashlights to be specific. For these exposures, we used handheld flashlights like those you might keep around the house for emergencies. The distance and size of the foreground determines the strength of the light and the painting time needed. It’s part of that experimentation I mentioned earlier. You just have to try a few combinations and see what works best. The “painting” technique involved moving the light around the surface of the rock in rapid zigzag motions, making sure to cover the desired area in a short time. In the case of the star trail photo, the arch was lit for only thirty seconds while the stars were exposed for a full hour.

If night photography is your cup of tea, you might consider reading Creative Night by Harold Davis. His book is chock full of great ideas and techniques. In addition, workshops are available from a variety of sources. Moab Photo Tours (this is the one I took) offers an excellent workshop that features world-renowned landscape photographer, Tom Till. Lance Kemig and his company, The Night Skye, also offer domestic as well as oversees workshops in night photography. To get started on your own, you may want to visit The Nocturnes, an abundant source of information.

You can see more of my night photos here.

HDR on a Leash

HDRI is a hot topic these days. It stands for High Dynamic Range Imaging, referring to techniques that capture a broader range of bright and dark tones than normal. HDR may sound intimidating at first, but it attempts to address a simple problem. Try shooting around sunrise or sunset and you will either have to expose for the sky or the foreground, not both. If you expose for the sky, the foreground will be dark. And if you expose for the foreground, the sky will be brilliant white. That’s because neither camera sensors nor film are capable of capturing huge differences in contrast.

So, what’s unique about HDR? It’s all about digital. With digital cameras, multishot techniques can be combined more easily with software to extend the dynamic range. The basic idea is to shoot as many frames as necessary to cover the contrast range in the scene. The main prerequisite is that the frames must be identical in every way except shutter speed, which you change to control exposure. Once back at your computer, special software is used to merge the frames into an output image. This results in a single image that has a more balanced tone range.

So far, so good you might say. But there are pitfalls. The HDR software used to blend photos tends to be complex, involving numerous toggles, switches and processing options. These features are needed because the software can make no assumption about your vision or intentions for the image. The photographer has to toggle the various program options to achieve a desired outcome.

I own three different HDR programs, and have experimented with hundreds of high dynamic range images. While I hardly quality as an HDR expert, I am keen enough to have noticed three main irregularities in the use of HDR software during my long hours of post-processing.

1) HDR software does not always produce a usable outcome, regardless of settings. I’ve seen many instances where the resulting image is so hideous that no permutation is salvageable.

2) HDR software can yield images that lack believability. This is great if the photo represents a fantasy land, but it doesn’t work for nature photography. In most cases, HDR techniques should be transparent to the viewer, unless your goal is to highlight the exaggerated effects.

3) HDR software can increase noise and reduce clarity. Be sure to zoom the final image at 100% to check for quality problems. In my experience, noise is often a killer problem.

Am I suggesting to avoid HDR software? Certainly not. But I do suggest you use it judiciously. Put HDR on a leash! Be willing to accept that it will not work for all images. At times, it does wonders and sometimes it fails miserably. And when it does fail, I always revert to manual HDR.

Manual HDR is my favorite approach for dealing with high dynamic range images. The capture process is the same as above but here the job of blending tones is done manually. The approach is easy for those well versed in Photoshop. The bracketed images are opened as layers, a mask is applied to each layer, and the desired tones are selectively painted onto the base layer using a brush. The result is a tone balanced image that looks realistic and is free of synthetic noise.

The big online bookstores carry several good titles on the subject of HDR photography. To get started, you may want to consider reading this HDR Tutorial by Trey Ratcliff. In addition, this article at The Luminous Landscape discusses a digital blending technique using Photoshop. Photomatix is currently the most popular HDR software, but another good alternative is FDRTools.