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Old 19-10-2002, 09:07 AM   #4
crazypaladin
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Join Date: Jan 2000
Posts: 2,375
Guide to Filters - Part I
Skylight and UV(0)

When you first buy your lens, u should consider buying a Skylight or UV(0) filter. The main function of the two filters is to protect the lens against debris, dust, water droplets and other foreign matters. Skylight is a (very) little pinkish, and UV(0) is colourless and will reduce a little haze. Always try to buy the best quality filter you can afford, from established brands such as or B+W.


Polarizers (circular and linear)

The Polarizing filter is one of the most useful filters for many photographers. A polarizing filter will eliminate reflections from a non-metallic surface. Let's say you're taking a picture of a lake with Japanese Koi swimming in it. However, you can't really see the fishes because the water is reflecting the sky. So you fit a polarizing filter on your lens and rotate it until the reflections are eliminated, so that you can see the bottom of the lake ! The same principle can be used if you're shooting through glass. As long as the reflection is not by a metallic surface, it can be removed through a polarizer.

Another use for polarizers would be to darken the skies. Polarizers can be used to deepen the blue in the sky. It can be used to bring out dramatic cloud formations, and to give the picture more punch. The elimination of reflection in the picture means colours are more saturated and has more impact. However, the blue skies trick will only work if the sky is already blue. It will not turn an overcast grey sky blue! You need to have blue skies, and the sun should be around 45 degrees to the area of the sky you intend to deepen the blue. You lose around 2 stops of light when you use a polarizer. So either use a faster film, or bring along a tripod.

Because of the electronics used in AF cameras, you are recommended by the camera manufacturers to use a circular polarizer, instead of a linear polarizer. Linear polarizers will not damage your camera, but your meter readings might not be correct. So when you buy a polarizer, always tell the sales-person you have a AF camera if you have one, so that he will not give you a linear polarizer by mistake.


Sunset and graduated filters

When the sky is much brighter than the ground, the contrast in the scene may be too high for your film to register. You'd end up with a picture with correctly exposed ground, but overexposed sky. Or a correctly exposed sky but underexposed ground. This is especially true if you use slide films.

So what should you do ? The answer is to lower the contrast of the scene so that both areas can fit into the latitude of the film. Graduated filters are filters with which are half-coloured, and half-clear. The coloured portion serves to darken the bright areas of the scene, to bring it in line with the darker areas. Graduated comes in a wide variety of colours, from orange to blue, to mauve and even tobacco colour. Lee filters and Cokin produce an entire range of graduated filters in every conceiveable colour. Do check out the whole collection!


Close-up filters

Want to do some close-up shots without paying for a macro-lens? Close-up filters act like magnifying glass, magnifying the size of the image so that it appears bigger on the negative. They come in many degrees/strengths, indicated by the diopters. The higher the magnification, the higher the number. Typically, it comes in a series, from +1 to +5. High quality close-up filters consist of 2 or more elements, offering superior optics over the single element type. Close-up filters are a cheap way of getting into close-up photography, and they are worth looking at if you do not need such high-power magnification or do close-ups often. Both Nikon and Canon offer highly-corrected versions of close-up filters as well.


Taken from http://www.cathayphoto.com.sg
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