Variation on a Theme III: Waterfall
Originally uploaded by mikeygibran
The Idea
While a long exposure at night can result in fantasy scenes with light trails and skies lit up like day by streetlights, a long exposure during daylight will typically result in so much light that the image is completely washed out. I have been experimenting with using a very dark filter to block enough light out to leave the shutter open for minutes at a time and still achieved good exposure.
Setup-at-a-Glance
Camera: dslr - Nikon d40
Lens: kit zoom - Nikon 18-55mm f/3.5-5.6
Filters: ND filter - B+W neutral density filter, 10 stop
Mount: tripod - Manfrotto Modo Max
Behind the shot
This photo is from Great Falls park in Maryland. It’s another attempt at daylight long exposure. The amount of light from the sun is overwhelming to a long exposure shot. You may be able to set the aperture way down, say f/20-32 depending on your lens, but even then having the shutter open for minutes at a time will still result in frames that are solid white. That is unless you put something in front of the lens to block lots of light – enter the neutral density filter. The filter looks a bit like the glass in a welding helmet, very dark. It blocks light equally across the visible spectrum, meaning it doesn’t color the image or that it is “neutral”, hence the name.
By using this type of filter, you can achieve the same results using long exposure shots during the daytime that you would get a night. There are lots of possibilities including turning water into a fantasy land mass of clouds, to getting the same sorts of trails from vehicles that you would at night, but with different types of detail since you pick up the entire vehicle, not just the lights, to blurring crowds of people. Another nice trick with long exposure shots in the daytime is that you can use them to make people disappear, literally.
If you are trying to photograph a building, and there are not many people walking by, but you just still can’t seem to get a frame devoid of people, use a long exposure shot. The building will be in the frame, not moving, the whole time, while any given walking person will only be in a specific spot for a brief time, at most a few seconds. Once you expose the photo, say for 120 seconds, the contribution to the image from that one person being there for 1 second, maybe 2, is minimal, and they disappear! Note that this won’t work with people standing around, or with huge crowds of people because you need to be able to see any given part of the building for substantially longer that the amount of time when there are people in front of it. It sort of “averages” out the people.
Process
So far I have found the best way to set these photos up, with my camera, is with a three step process: align the shot, add the filter, then set exposure. I align the camera and lens in automatic focus mode to get the exact image zoom, camera positioning, and focus I want while there is still enough light coming through the lens. Also, keeping the camera in autofocus mode prevents the focus ring from turning while you put the filter on. After setting up the frame and focusing, the filter goes on and the camera can then be put into manual focus mode. By putting the camera back into manual focus mode the camera will stay on the focus you've just set and not hunt for focus when you press the shutter release. If you leave the camera in autofocus with the filter on, it will most likely not have enough light coming through the lens to get proper focus and will just keeping searching. The last step is to use trial and error to dial in on the desired exposure setting, best done with manually setting the aperture and shutter until the desired image is achieved. You can tweak the balance between the aperture and shutter to get the best combination of depth of field and motion blur for the image you are trying to achieve.
