(© Ian Plant) I recently spent a week photographing Acadia National Park in Maine. Although I was drawn there by the gorgeous display of fall color, it is water more than anything else that defines Acadia and ends up being an important element of most photographs of the park. Here are some tips for successfully incorporating moving water into your photographs.
Water has energy and movement, so it is best to choose a shutter speed that captures that energy, to a certain extent. Typcially, some amount of motion blur is best when photographing water. If you use too high of a shutter speed, you end up freezing the action too much, leaving the moving water looking like static ice. The amount of motion blur you need to get the look just right depends on the subject, the volume and speed of the moving water, and personal taste. For example, for the image above, I found that a shutter speed of 1/6 second was perfect for capturing the movement of the waves striking the shore, creating just enough motion blur to imply a sense of motion and direction without losing texture and detail in the moving water. This is where digital cameras really come in handy, as they allow you to experiment with different shutter speeds and review the results instantly on you LCD screen until you get the look you are after.
A fun technique is to look for swirl eddies in a watercourse and make them the focus of your composition. Fast moving eddies, such as the one above, require relatively shorter shutter speeds (in this case, 1/2 second); slower moving eddies might require exposures that are several seconds long (or more) to complete the swirl pattern. As always, you want to pick a shutter speed that allows the water to blur in an interesting way, without destroying detail and texture in the water.
With smaller streams, longer shutter speeds can be used to create a "silky" look to the water. This technique often doesn't work with fast-moving, high-volume streams as the longer exposure results in an undifferentiated mass of blank white water. For this intimate brook, a shutter speed of 1/2 second allowed me to capture a silky smooth look, while still retaining enough detail in the water to keep it from looking featureless.
Remember, experiment freely with shutter speeds, reviewing each attempt on your camera's LCD until you find the look you want. Adjust aperture and ISO as necessary to get the optimal shutter speed, and use neutral density and polarizer filters if you need longer exposure times. A polarizer filter is also useful for removing distracting glare from wet rocks and foliage, which will increase contrast and color saturation in your photos. A sturdy tripod (of course) is necessary when using long exposures.