If there is one kind of photograph that never ceases to impress, it is a long exposure shot of flowing water. The shot can illustrate the ebb and flow of sea water on the coast; of a graceful waterfall; of a rapidly flowing river or stream; or even of water gushing from a tap.
Every photographer wants to master flowing water photography because it convinces others that the photographer knows what he or she is doing.
In order to photograph flowing water a digital SLR camera is recommended, together with the basic kit lens. However, an advanced compact camera with aperture priority mode is also an option, as a shallow depth-of-field is not required. (Compact cameras are incapable of giving a shallow depth-of-field). A sturdy tripod is essential to prevent camera shake.
To photograph flowing water a long shutter speed is needed. This records the motion of the water whilst the camera’s shutter is open. (If the camera is left in Automatic (Auto) or Program (P) mode, pin-sharp shots will be captured with hardly a trace of motion). By using Aperture priority (A) mode, the aperture for the shot remains constant whilst the camera’s built-in meter selects the necessary shutter speed for a good exposure.
But what aperture is best? Since a long shutter speed is needed it is clear that a small aperture has to be used as that will limit the amount of light reaching the camera’s sensor. In fact, it’s best to use the smallest aperture (the highest f/number). This will be around f/22 with a standard kit lens.
An alternative to using Aperture priority mode is to switch the camera to Shutter priority mode. When that is selected it is the shutter speed that remains constant with the aperture size being variable. The result, nevertheless, will be exactly the same as the two modes are inversely proportional. Thus, selecting f/22 in Aperture priority mode will give, say, a one second exposure; in Shutter priority mode a one second exposure will make the camera select an aperture of f/22.
It is best to select the lowest ISO setting when shooting flowing water. By choosing ISO 100 or 200, the camera’s sensor will be set to its minimum sensitivity to light, which means that the shots acquired will be of the best quality for long exposure times.
The White Balance should ideally be set to Daylight, but if the shots are taken in camera RAW this will not be an issue as the White Balance can be changed later on with camera RAW software such as Adobe Photoshop or with the camera’s own RAW software.
It is recommended that the camera’s self-timer is set to about 2 seconds in order to prevent nudging when the shutter is pressed.
So, with the camera attached to the tripod, the frame is composed and the tripod head is locked to prevent the camera from moving. Next, the focus is set on anything that is approximately one-third of the way into the scene and the shutter speed is noted. If the speed is 1/10sec or slower then the shot can be taken. If the speed is faster than this (recall that the smallest aperture is being used) then the amount of light reaching the sensor has to be reduced before the shot is taken.
The amount of light falling onto the sensor is reduced by using a neutral density filter, if a digital SLR camera is being used. If a compact camera is being used then it is best to wait until later on in the day when it gets a bit darker. A neutral density filter is ideal though, as it gets the job done there and then. Again, if the shutter speed is 1/10sec or less then the shot can be taken.
Finally, the resulting shot is checked on the camera’s LCD screen. If it is too dark, an exposure compensation of +0.3 to +0.7 stops is dialed in and the shot taken again. If the shot is too bright, an exposure compensation of -0.3 to -0.7 stops is dialed in.
The final image will show perfectly blurred, moving water.
Source by Vic George
