Creative Field Techniques - Equipment for Long Exposure Waterscapes
The image above was shot one morning on Biscayne Bay when the fog lay heavily over the water. Despite the sun rise, the fog remained consistent and became illuminated by the rising sun. I was mesmerized by it and wanted to capture a scene that emphasized the mood. I set the exposure so that the shutter remained opened for 10 seconds. By doing so, all the movement in the water and all the light reflecting on the surface blurred together to appear smooth.
But there is a caveat. Setting up for a long exposure requires certain equipment. First, the camera must be secured on a tripod with no risk of movement. Notice in the photo above how textured the water is from the wave action. To smooth that out, I would need to expose the scene for several seconds and that's why the camera is on a tripod. There is another caveat. The longer the shutter is open, the greater is the exposure or the amount of light that enters the lens and hits the camera's sensor. Because of this, the photographer has to make camera setting adjustments to avoid over exposing the scene. However, even with appropriate settings, too much light may still be getting into the scene. So what to do, what to do?
Bring out the filters. Filters are basically glass or resin plates that are darkened and meant to be placed in front of the lens. In the photo above, I laid out several filters; notice how they differ in darkness. The darker the filter, the lesser the amount of light that hits the camera sensor when the filter is placed in front of the lens. Some filters are darkened evenly throughout the plate, these are called neutral density. There are four neutral density filters in the photo above (top left one and the three on the bottom). Now take a look at the three photos below to see the effect. The first one decreases the light by one stop (one stop down means half the amount of light). The second one drops the light by 3 stops (essentially 1/8 the amount of light is allowed in). And the third, wow, that one reduces the light by 10 stops (1/1000, or something like that)!
More than one filter can be used at a time. For instance, if I combine all three filters pictured above, I would have a reduction in light by 14 stops (10+3+1). The other two filters in the photo above are called graduated neutral density filters. These come in various types and a discussion on them requires a separate blog, but basically they are designed to cut light out of a portion of the photo. A good example of their use is when the sun is setting over the water. As you see in the photo below, the brightest part of the photo is darkened above, leaving the lower portion in tact.
At this point, you may think that seems easy, just add a filter and set the shutter speed for 10 seconds or more. This may work much of the time, but sometimes, faster speeds are preferable when we like to see some texture in the water. Below is one example. The shutter speed was set at 1.6 sec. This was long enough to give the water a blur, but not so long as to remove all evidence of movement. Those darker areas of the water are oyster bars and I wanted their contrast and texture to stand out.
As if you didn't have enough to think about when setting up for long exposure, now consider clouds in the sky, which often times come with waterscapes. Long exposures can very much affect the appearance of the clouds, especially when they are moving. With long exposures, you can add drama and impact to a photo if clouds are present. Here's an example where I used a 58-sec exposure. This allowed time for those clouds to move quite a distance across the sky.
In summary, long exposure waterscapes take practice, experimentation, and creative thought, an understanding of exposure, and some additional equipment beyond the camera and lens. If you are venturing into long exposure images, my best advice to you is to simply experiment with different shutter speeds and various water locations. The behavior of water can dramatically differ from one location to another (i.e., waterfalls, beaches, ponds, rivers, etc) and can be influenced greatly by tides and winds. But once you get into it, you will surely become addicted. Thank you for looking on!
You can learn more from my YouTube video titled "Long Exposure Waterscapes on a Remote & Wild Florida Beach."
Here are some links for filter products:
If you lens is not 72mm, search adapter rings for the correct diameter (mm) size.
Here is a link for a 67mm lens adapter
If you are interested in more intensive instruction on long exposure waterscapes or other types of photography, my workshops are available to individuals or pairs and are custom-designed to help the novice or intermediate photographer meet his or her goals. Contact me at firstname.lastname@example.org or visit my workshop page.