The Essentials: Long exposures demand the use of a tripod. The sturdier the better should the wind decide to not cooperate. If the wind is constant, a flimsy tripod will reveal its shortcomings in the form of a soft image. Exposures may be 30 seconds or longer, so be sure to set your camera to Long Exposure Noise Reduction. During a long exposure, the digital sensor builds up heat, which translates to digital noise. With the camera set to LENR, the file undergoes “in camera processing” negating the effect of the digital noise. The drawback is it takes time to process the photo— an initial 30-second exposure requires 30 seconds of processing time.
The Glow or the Silhouette? Great post-sunset light comes from a gorgeous alpenglow. Two primary options await the eager photographer—go behind the subject with the bright sky as a backdrop to create a silhouette or use the bounce light of the alpenglow to bathe the subject in the reflected warm tones from the sky. If the subject is small and can be maneuvered around easily, work quickly to go home with both scenarios.
Shoot In RAW: RAW capture provides the option to more effectively alter the color balance. It also allows more tweaking of the exposure if needed. In that obtaining a proper exposure may be tricky, more detail can be recovered from a RAW file than a jpg.
Work the Polarizer: On one of my post-sunset shoots, I experimented with my polarizer to see its effect even though the sun had set. To my amazement, as long as I adhered to the 90 degrees from the sun rule, the polarizer worked equally as well to darken the sky as if the sun was shining brightly. While it will have no effect if you’re opting for a silhouetted subject shot 180 degrees from the sun, it still works its wonders at right angles.
Low ISO: While it may seem logical to boost the ISO because it’s dark, don’t. Keep the camera set to a low ISO and let the shutter stay open for longer periods of time. The lower the ISO, the lower the noise. You may even wind up with a bonus special effect of moving clouds or moody flowing water. Monitor your histogram after every exposure and adjust the time accordingly. The highlights shouldn’t be a problem, but be careful to not block up the shadows.
And don’t overlook predawn and dawn light as the same principles apply.