Polarization Filter and its use in Photography
Author of text and photos: Goran Katić
Polarization filter, used in color as well as black and white photography, is the most used where there is a need of reducing contrast of the sky and earth (when the sky looks burned up it’s used to get a correctly exposed earth surface).
Photo #1: Photographed without polarization filter, notice burned up of the sky. Photo #2: taken with filter, sky is no longer burned and fits better with surroundings. Clouds are much more detailed and colors fuller.
Photo #3: Photographed without polarization filter.
Photo #4: Photographed with polarization filter.
That is not its only function, though. Second worst thing to a photographer is photographing reflective surfaces. Reflections of transparent surfaces, like glass and metal, give undesirable effects which only spoil the final effect/atmosphere of the photograph.
To avoid such problems, polarization filter is put on the lens. By turning it in certain directions it can prevent the unwanted reflective rays of light from going trough the lens and reaching the film or a photo sensor. Although, it’s successful in blocking water reflections, it’s not as successful in blocking reflections from the metal.
Unlike many other filters, polarization filter, thanks to its density, reduces the strength/light flow which travels trough and ends on the film, that’s why it needs 2 to 3 times longer exposure. When using this filter pay attention to exposure correction and strength of the effect you wish to accomplish, to avoid what happened to the Photo #4.
With SLR cameras, polarization filter’s effect (reduced reflection effect) can be seen right there in the viewfinder, while with other camera types filter rotation needs to be preset before put on the camera lens.
