Water as one of the primordial elements has been a constant source of fascination for the human imagination, and offers a host of stunning images for photographers. The quietness of a lake in the mountains, reflecting the beauty of its pristine natural environment, forms a fascinating contrast to the swift flow of a brook running through the forest undergrowth, for example. To better capture the brilliant colors and contrasts in images of natural scenery, photographers can use polarizing filters. However, taking really good shots is sometimes more about having a bit of background knowledge and creative thinking than any special accessories.
Reflections on water surface
Filters still have their part to play, even in our age of digital photography and image processing programs. Indeed, filters can often achieve effects that are beyond the capabilities of reprocessing programs, or would be extremely time-consuming to replicate with that technology. A polarizing (POL) filter can be the ideal way to deal with unwanted reflections. POL filters filter out reflections on non-metallic surfaces, i.e., wherever some of the incident light at an oblique angle is reflected by the object, and some is absorbed by it. In this kind of partial reflection situation, which can occur with water, glass, or enamelled surfaces, along with the reflection ray as such, there is also a refraction ray. The POL filter eliminates the reflection rays so that the reflections are no longer visible in the image.
The key points for the successful use of a POL filter are to pick the right place to take the photograph and to select the correct filter orientation. To pick the best position for the polarization effect, simply turn the filter and look through the viewfinder. The rule of thumb for a good result is to take the photograph approximately at right-angles to the direction of the sun.
Photo tip: POL filters can be used to create some amazing effects for water surfaces in particular. Eliminating the reflections from the crystal-clear water surface lets the viewer’s eye penetrate right down to the bottom of the lake. This gives the image extra depth and creates an unusual mix of spatial perceptions. The eye is able to wander over the bottom of the lake, float over the water surface beside the shore, and explore the surrounding environment. The impression is one of three distinct levels – under, on and along the water surface.
Long exposure times
We have all seen images of a waterfall or river that give the water a soft, silky look. Such photos are often taken with a neutral density (ND) filter (sometimes also referred to as “gray filters”). Depending on how fast the water is flowing, achieving this sort of softness in the image may require a long exposure time, sometimes up to several seconds. An ND filter allows this kind of extended exposure, even under bright light, through a uniform and color-neutral reduction in the incident light.
In terms of picture composition, this leaves plenty of scope to vary the depth of field. Reducing the light level and increasing the exposure time simply by stopping down the lens would have the effect of increasing the depth of field in the photograph. Without the use of a filter, there would be no way to obtain the contrasts between sharp and blurred contours that are achievable with a wide aperture. Using an ND filter can lend an attractive softness to running water surfaces, even when using a wide aperture, because the filter prevents excessive incident light and the resulting overexposure, in spite of the wide aperture.
Another argument against stopping down is diffraction blur: this phenomenon becomes increasingly noticeable the more the lens is stopped down, with detrimental effects on image quality. With an ND filter, the exposure time shutter speed can be extended without stopping down the lens. This means you can select the optimum lens aperture setting for a superb photographic outcome.
ND filters are available in a range of different strengths. While in principle it is possible to combine several strengths by fitting multiple filters in front of a lens, this is not recommended. One strong filter is always better than two weak ones. Each filter placed in front of the lens means a further decrease in image quality.
And of course this is even more reason to use a tripod, as the only way to achieve the long exposures required for soft water images.
Frozen in time
The kinetics of water have a special fascination for the human eye. Falling drops or the foam of waves breaking against rocky cliffs require short exposure times and a certain amount of photographic skill. Exposure times of, say, 1/500 to around 1/2,000 second are sufficiently short to “freeze” splashing water, for example.
Sunny conditions are a distinct advantage when using exposure times as short as this. Wherever possible, the ISO setting on the camera should not be increased. While this improves the light sensitivity of the sensor and allows even shorter exposure times, the image quality may be impaired by image noise. Your photos should therefore be taken at the lowest possible setting.
The dynamic impression conveyed by splashing water can be further highlighted by playing with the perspective, particularly by making the water look as if it were rushing out of the image toward the viewer. The time of day and camera angle should ideally be chosen so as to create a sort of natural backlighting effect.
Backlighting allows the use of short exposure times without supplementary light sources, and ideally enhances the visual impact of bubbling water. Geysers shooting up out of the ground or waterfalls plummeting down from above are ideal subjects for backlit images with short exposure times.
Practical tip: Backlighting can also be created by artificial means, for example with external light sources or a flash in slave mode. This kind of technique can be used in a darkened space, such as a bathroom, to capture striking images of water dripping from the shower head. You first have to open the camera shutter in the darkened room. This is done with a remote-control release, which in the “bulb” (“B”) setting keeps the camera exposed for however long you press the shutter. Now, with the water trickling from the handheld shower head and with the shutter open, you can flash sideways from the rear towards the drops of water from the handheld shower, and then end the exposure. The result is an image with sharply defined water drops.
Problems and prevention
As we have seen, water is a fascinating subject for photographers. But water in any form – individual drops, puddles reflecting the sky above, creeks or waterfalls – leaves traces on the lens, and is a potential hazard for your valuable photographic equipment.
Even minuscule drops or water vapor will leave stains on the front lens. These can be removed with a microfibre cloth (80% polyester, 20% polyamide) and a special cleaning fluid. This should be done carefully, since any rough treatment could damage the coating on these high-quality lenses. We recommend the Carl Zeiss Lens Cleaning Kit for this purpose.
It is also important to remember that there are likely to be impurities in the water deposits on the lens. Any water in the natural environment will almost inevitably contain some dirt particles, potentially causing minute scouring in the front lens during cleaning. Along with its primary filtering function, a UV filter also provides mechanical protection against water and dirt particles. This is already sufficient reason for the use of these filters for any outdoor photography, particularly by the sea and on beaches, where there is likely to be salt and sand in the air blowing around the lens.
UV filters are primarily designed for photography at high altitudes above 2,000 meters, or beside the sea. They filter out ultraviolet light, which is not visible to the human eye. These rays from the end of the optical spectrum possess more energy than visible light, and are more strongly refracted by the lens. UV light mixes with visible light as it reaches the sensor, potentially causing blurring. UV filters provide ideal protection for the front lens since they are colorless and have no effect on the image colors.
Quality is the key
But obviously it is important to use quality filters. Depending on the design, a filter adds a layer of glass and air to the lens. The light rays have to traverse these layers on their way to the sensor, causing minimal reflection and refraction. On the basis of the elementary laws of physics, this inevitably slightly impairs the sharpness of the image. So quality is important for filters, just as it is for lenses. Your filter must have a multilayer antireflective coating and must be ground perfectly flat, and set in a high-quality fitting.
A well-finished fitting is essential for attaching the filter correctly to the lens. This ensures that the filter is fitted precisely at right-angles to the optical axis, in spite of constantly being screwed on and off.
With a high-quality filter, you can safely ignore any minor impairment in image quality, particularly since, without an ND filter, it would simply not be possible to catch the “soft wave” effect on water surfaces and the dynamism of water as an ever-restless medium. There is then also no problem with using a POL filter to eliminate unwanted reflections and boost color saturation.