Flowing Water

Flowing water is a photographic subject that is very popular. When it is done well the results can be very beautiful and there is something about the smooth silky look that appeals to everyone. Most people have a stream or river close by so its quite easy to get out and start taking great photos. It’s a favourite subject of mine and I find it very relaxing as it forces me to walk slowly through the woods or along the riverside and really see the beauty of simple natural locations.
It is all done ‘in camera’, that is to say that there is no faking it with Photoshop or any other software package. It is a straightforward technique but there are a few rules to follow to achieve success.

Equipment
A tripod is absolutely essential, as is some means of firing the shutter without touching the camera. That can be a cable release, an infra red remote control or, just as good and free, the camera’s self timer. If your camera is fancy enough to have mirror lock up then use that as well. It is too bad that this essential feature is left off of most cameras these days. When you fire the shutter the reflex mirror moves very rapidly and gives quite a lot of vibration to the camera body even on a tripod. Mirror lock up enable the user to manually raise the mirror before the shot is fired so that this source of vibration is eliminated. Back when dinosaurs roamed the earth and cameras had mechanical self timers, the mirror was raised when the self timer lever was rotating, so you got this ‘advanced’ feature free. Nowadays you have to pay a fortune for a pro level camera to get it.

Shooting
There are two factors that are most important in these moving water images and they are the light level and the volume of water in the river.
To achieve the silky effect it is necessary to have quite long exposures, between a quarter of a second and 3-4 seconds being the normals. It is therefore essential to have low light conditions. Overcast days are good times to go out, as is late afternoon/evening. Midday and strong sunshine are to be avoided unless the water is in woodland sufficiently thick to block most of the sunlight. If the light is still a bit bright you can use either a polariser or a neutral density filter to block the light and extend exposure times.
The second factor, that of water flow, is the most important factor. Unfortunately film, and digital sensors, has a low dynamic range. That is to say that the range between overexposed and underexposed is small, only two stops for slide film and digital. If the water is very frothy or there is sun directly on the water, the white of the bubbles and foam will overexpose completely. It will become a detail-less white mass, while the rest of the image will be too dark. Sun directly on the water is a real no-no, but even in the shade a wild and frothy river can be hard to get good results from.
If you want good shots of the water with detail in the shadows like this then look for a small fall with not much white foam. During the long exposure the detail will record in the scene, ie the rocks and the darker water while the white streaks from the bubbles builds up to give the white misty effect. This is not to say that you cannot take photos of wild water. It just means that you have to be a bit more selective about how you go about it and try to take a part of the scene with no shadow areas. Using a telephoto will enable you to take a part of the scene. Anything that is not water in the scene will be reduced to a silhouette, so rocks and trees can be used to form interesting shapes as part of the scene such as the rocks at the foot of the falls here.
With really big volumes of water, such as the photo of Montmorency Falls here, a better effect can be obtained by using a faster speed. The silky effect is beautiful but it will mask the volume of water passing. The subject of photos like the Montmorency is the volume of water. If I had used a long shutter speed for this shot it would have reduced to a mass of detail-less white.

Exposure
There aren’t many difficulties involved. In a shaded scene the camera’s meter will give a perfect reading. Its worth taking a shot at -0.5 stop just to be sure that you get one with the water correctly exposed. With wilder water and of there is sun on the scene then you will need to bracket and take a few shots underexposed in order to keep detail in the highlights. However if there is too much contrast in the scene then it will be beyond the ability of film/sensor to capture and you will have to be more selective in the image or come back another time.

Recommended shutter speeds
1/250th and faster. This will freeze the motion completely. Suitable for capturing spray and droplets.
1/125th to 1/250th. Motion part frozen with some movement apparent. The worst speeds for water as the motion is neither stopped nor interesting enough to make a good image.
1/15th to 1/60th. Fast moving water significantly blurred. This is a good range for faster moving water as the volume of water will be visible and the sense of motion will make a good image. For very large volumes of water (like the Montmorency shot here) 1/60th is a good bet.
¼ to 1/15th. Complete blurring of details. The misty water effect is obtained in this shutter speed range.
¼ and longer. All details completely blurred. These speeds give fantastic results but you need very low light and very low contrast in the scene to avoid overexposure. Woodland streams just around sunset are a happy hunting ground.