Polarizing Filters and UV Filters
There are several different kinds of lens filters serious photographers use regularly. If you have an SLR camera, you will be able to buy filters that screw onto the front of the lens. Two of the most basic filters are polarizing filters and UV filters.
UV filters
A UV filter is the most common type of lens filter. It serves to partially remove the incoming ultraviolet light. Ultraviolet light isn’t a problem at sea level but as you gain altitude, UV levels increase. The blue color you see in the distance in landscape photos is generally produced by ultra violet light. Some film types are UV sensitive, and will result in a bluish tint if used at high altitude. A UV filter will solve this problem, but I understand that most digital sensors are not sensitive to ultraviolet light, so a UV filter isn’t necessary unless you are using film.
A UV filter on a digital camera probably does very little except protect the front of the lens, and perhaps help to reduce haze or smog. In most cases if you have a digital camera you won’t care about ultraviolet light, so it would be just as effective to use a plain filter of clear optical glass to avoid scratching your lens.
Polarizing filters
Polarizing filters are an entirely different type of filter. We all know that light is a series of waves. Normal light has waves that undulate in all directions. A polarizing filter is like a net that only allows light waves going in a particular direction to get through. Light reflected from certain surfaces is also polarised in a particular direction, including some of the light reflected from the sky. A polarizing filter can be used to prevent this light from entering the lens, thus reducing glare and darkening the colour of the sky.
A polarizing filter is generally used to produce deep, rich blue skies. Most filters are attached to the lens in a fixed position but a polarizing filter is rotated by the photographer. As the filter rotates, the polarizing effect increases and then decreases – looking through the lens, you simply turn the filter until you like the effect. With a polarizing filter, blue skies look great and even better when there are some white fluffy clouds to provide contrast. Be careful, though if you are using a really wide angle lens (24mm or wider)The polarizing effect may not stretch across the image frame and you could end up with an unattractive two tone sky.
A polarizing filter can be used to increase color saturation in many different areas. Green foliage and even red roof tiles can look extremely vibrant. Because the color saturation is increased, your shadows may turn out much darker than you had planned, and hide or darken some of the subject, so watch out for that.
Tags: polarizing filter, polarizing filters, untraviolet light, uv filter, uv filters
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An SLR camera is single lense reflex? How does that differ from a “normal” camera?
There are three basic types of camera – 35 mm. film, SLR, and pocket digital. I was referring to an SLR as opposed to a pocket digital. I plan to try some filter techniques for a pocket digital camera in the next few days, and post about my results. Sorry to cause confusion!