Rivers, streams, cascades and waterfalls. These very words paint a very distinct mental picture in most people's mind. When trying to capture images of moving water, there are two different ways - frozen in time, or flowing as seen in some of the "cottony effect" images. Both ways of photographing these geologic wonders are very easy to do.
The creative digital camera tool used to control both forms of motion is shutter speed. To freeze the water, use a fast shutter speed. Exactly how fast takes some experimentation, because it depends on how fast the water is moving.
To show water flowing, a slow shutter speed is used, but again the exact shutter speed needed depends on how fast the water is moving, so it may take a few shots, with a shutter speed change in between, to get the proper effect.
For fast flowing water, a shutter speed as fast as 1/15 second can create a minimal amount of the cottony effect, while at other times with slower flowing water, a 2-second speed may give you the effect you want. It all depends in the variable of how fast the water is moving and the amount of the effect you want.
Unfortunately, there isn't a magical chart yet that will tell you what shutter speed to use under which conditions. The only way to learn how to create the effect is to experiment by shooting scenes at each of the shutter speeds between and including 1/15 second and 2 seconds. Start at one end of this range and shoot an image at each setting between the two extremes. Note the shutter speed setting for the image having the correct amount of cottony effect. Compare this with the approximate speed of the water.
For "unknown" water with an "average" flow rate (whatever average is as it relates to flowing water), I usually start at 1/4 second and then use a shutter speed both one stop over and one stop under from the initial 1/4 second shot. This is known as bracketing and is a good method of normally assuring at least one of your shots has the right amount of effect you want. For faster water, start at 1/8 second; for slower water start at 1/2 second; in each case always bracket. As you gain experience shooting flowing water, you will be able to accurately estimate what shutter speed you will need.
Because we are using such slow shutter speeds, a sturdy support for your camera is needed to shoot clear, crisp photos. Of course, the best support is a tripod. Another accessory you will eventually want used with a tripod to prevent camera movement is a cable release.
If you don't have a cable release or if your camera doesn't have a cable release socket, you can use your camera's self-timer feature to trip your camera's shutter. After all, the water is moving, but the flowage itself isn't going anywhere, so take your time and enjoy the shoot.
If you don't have a tripod or you did not bring yours along, a good substitute to steady your camera is a wall, rock, fence, tree or any other sturdy support. A monopod works well and it also doubles as a walking staff. When not using a tripod or other steady support, use good breathing and camera-holding techniques. With image stabilization and good camera-holding techniques, most people should be able to handhold at two-stops slower than without stabilization or about 1/8th second.
Sensor speed can be another consideration when shooting moving water, especially if your subject is in the shade. It may be very difficult to get a slow enough shutter speed if your camera is set to a low ISO. Instead, use a faster ISO of 400 or 800 to allow you to get down to the slower shutter speeds. Higher ISOs don't require as much light, so you can shoot at a slower shutter speed.
On a bright day and very slow moving water, sometimes even a high ISO of 800 might not be enough to get the slow shutter speed you need for a certain shot. When faced with this situation, use a neutral density filter. These filters reduce the amount of light reaching the sensor and come in several different intensities. Depending on the manufacture, they will mark the intensity of the filter by either a density number such as ND 0.3, or a filter factor such as 2X.
Common densities range from 0.1 to 0.9 while filter factors range from 2X to 8X. The amount of light reduced generally changes by 1/3 of a stop for each change in density or filter factor.
You can decide which filter you need by determining the slowest shutter speed your camera will allow you to shoot and comparing that speed to the shutter speed you want to shoot. That difference is in stops.
Then choose the neutral density filter for that number of stops. Usually, a 0.3 or 2X and a 0.6 or 4X will cover most of your needs. This gives you a 1-stop or 2-stop reduction in light, respectively if used singularly or a 3-stop reduction if stacked.
By using neutral density filters and shooting on a cloudy day or in shaded conditions, you can use a large depth-of-field setting such as f11 or f16. By using large-number f-stop settings, you will hold more of the foreground and background in focus than if you used a smaller f-stop. If you want the foreground or background blurred, then use a smaller number f/stop.
Another accessory nice accessory to have with you is a polarizing filter. A polarizing filter removes reflections from the wet rocks and quiet pools of water, perks up the colors of the scenes and acts as a two-stop neutral density filter.
If you have had problems getting the cottony effect in the past, using the techniques and tools discussed in this article will allow you to create beautiful cottony effect in your flowing water images.
If you liked this article, visit our website at Sunlight Media for more tips and techniques.
Ron
0 comments:
Post a Comment