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I went out one night last week to the shores of White House Creek with a wide-angle lens set to f/18 (or better) and a sheet of construction paper -- more about that after the photos themselves. I started out taking exposures at around a half-second, but was up to 30 seconds or more per exposure by the end of the set.

So about the construction paper: all cameras have a limited dynamic range (the amount of difference between "dark" and "light" they can handle in a single exposure), and the CCDs in most digital cameras still have a considerably narrower range than film did and tend to introduce ugly artifacts when the red channel is overexposed (not good for sunsets).

Generally the solution to this problem is to place a "neutral gradient" (or ND) filter on or in front of the lens to darken the bright sky, but leave the dark ground alone. Unfortunately good ND filters are expensive, and I've yet to find one that will work with my favorite wide angle lens. So this photo expedition was largely an excuse to try out an experiment in reducing the dynamic range using an old tried and true technique involving a moving sheet of black construction paper.

Here is the setup:

1. Frame, meter, and focus the scene.
2. Switch the camera to full manual.
3. Hold the top of the black construction paper, and place it as close to the lens as possible, with the bottom of the paper close to the bottom of the lens.
4. Trigger the shutter.
5. Slowly (or VERY slowly depending on the shutter speed), move the paper up, keeping that bright sky hidden behind the paper for as long as possible.

If the sun (or other bright object) is off to the side, hold and move the paper at an angle that will keep it hidden for as long as possible. For skies this tends to be parallel with the horizon line, but not always. For example, I used the mask at about a 45 degree angle for the shot above with the light post in it -- keeping the light post itself hidden until the end of the shot.

This low-tech masking technique is obviously more difficult the faster your exposure time is, but I found it to be easily manageable for scenes with exposures of 2 or 3 seconds or more.