Posts Tagged ‘digital camera’

Power of Circular Polorizer

authored on Saturday, September 12th 2009

Just a tiny twist on the polarized lens and magic happens. How kewl is that?!

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Have you ever wondered if you need to use photography filters with a digital camera? When digital cameras took over film cameras, the post production changed as well. The darkroom seems to have been replaced with a computer and graphics program, such as Adobe Photoshop. Although manipulation can be done after the image is taken, whether in the darkroom or computer, there is no real substitute for the original image being as close to the quality output desired in the first place.

The primary purpose of a photography filter is to enhance or change the picture. There are several different categories of filters as well as many different manufacturers. Another purpose for photography filters is to protect the camera lens. Filters are inexpensive when compared to the cost of replacing a camera lens. Often photographers use an all-purpose filter for this purpose, and exchange it for a more specialized filter when the subject calls for something a little different. Below is a list of some of the more common categories and filters available to today’s photography enthusiast.

Essential Filters:

The purpose of a clear filter is to protect the lens. It does not affect the exposure of the image. UV (Ultra Violet) filters help with removing some haze caused by ultra violet light. There are different types of polarizing filters. This filter is especially important because the software available today just does not come up to par with duplicating the results of using a polarizing filter at the time of exposure. When choosing a polarizing filter, decide if you need a linear or a circular polarizer. Basically, if you are using an auto-focus single-lens-reflex camera, you would need the circular polarizer. This is because of the beam splitting metering system that the digital camera uses.

Color Correction Filters:

While the polarizing filters mentioned in the previous paragraph are necessary even in the digital age, the color correction filters, however, are not as crucial to the success of the image outcome. This is because color correction filters manipulate the color, and the post production graphic manipulation programs (Such as Adobe Photoshop) can compensate pretty well for this. The basic need for these color correcting filters was to compensate for the difference in the temperature of the ambient light with the type of film being exposed. These filters are named with a number and a letter, such as 80A or 85B.

Special Effect Filters:

Special effect filters create fun and sometimes unusual effects. Examples of special effect filters are fog, sepia, and star filters. As their name suggests, they produce the named effect within the image. Perhaps the best special effect filter is actually not even referred to as a filter, but as a lens, and is called a “close-up lens.” They usually come in a set, and can be used in combination to achieve the desired close-up distance. They are much less expensive than purchasing a dedicated macro lens, and produce clear, brilliant images.

Black and White Filters:

Black and White filters rely on the principles of color separation to manipulate images for a desired effect. The choice of black and white filters is broken down by a color name along with a number. Theses filters work by absorbing their complementary color of light. For example, a yellow filter will absorb blue, and make the sky darker, which in turn can enhance the appearance of clouds in the sky against it. A yellow-green filter can minimize the effects of red that tungsten lighting can produce.

Transitioning from film to digital photography allowed me to blend the best of both processes. If you would like to learn from my experience visit a great casual site for sharing photographic tips, tricks, and shortcuts, as well as discussions about the latest photography equipment.

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Photographers often use polarizing filters to improve the appearance of the images they capture. With digital cameras many filters are no longer necessary and do not always work correctly. There is one filter, however, that is the most often used filter, and it is considered a necessity to a landscape photographer. Whether using a digital or a film camera a polarizing filter will increase color and eliminate reflections in your images.

To unlock the secret of the polarizing filter, you must use the filter correctly.
To use your filter, find the correct size filter to fit the lens you are currently using. (a 55mm polarizer for a 55mm lens etc). Secondly, screw the filter onto the front end of the lens (nearest the subject). After the filter is snugly attached to the lens, rotate the filter. Look through the viewfinder as you rotate the filter and you will see the results immediately. Your landscape images will take on a whole new look; skies will become more deep blue, clouds more brilliant and grass greener. If you stand at a 90-degree angle to the sun you will get the maximum effect from your filter. Do not stand with the sun in front of you or behind you to take the shot.

A polarizing filter, used properly, on an overcast day will saturate the colors of the wet leaves giving life to the image. Of course, you must be very careful on a low light day as a filter can make your images too dark. A polarizer will cut the amount of light reaching your film or sensor. To counteract the decreased light reaching the sensor or film, open the aperture or slow your shutter speed to compensate.

Even though using a polarizing filter has many benefits, which far outweigh the pitfalls, there are several pitfalls of using a polarizing filter. Most of the pitfalls can be avoided with a bit of knowledge.

The first thing one needs to know about a polarizing filter is that there are 2 different types. One is the linear polarizing filter the other is the circular polarizing filter. A circular or a linear filter will do exactly the same thing for your images; enhance them. To compare them, the circular filter is more expensive and the linear filter may not be the best choice for most cameras that use auto focus.

A linear filter will often ruin the performance of auto focus; the camera is unable to transform the information correctly coming from the filter. A circular polarizing filter has an added layer which scrambles the filtered light coming from the polarizer and the camera is able to read the information more clearly.

The extra layer in the circular filter is the main reason the circular is more expensive. But as you can see it is often well worth the extra expense. Also, be sure when you purchase a filter that there is no color cast in the filter. Some filters come with an odd cast, green or yellowish color; make sure your filter has only a neutral grey cast.

Another problem encountered with polarizing filters is found when using wide-angle lenses (28mm or wider). A wide-angle lens may see the rim of your filter, causing a darkening at the edges of the image. Also, the sky can become unevenly polarized as polarization varies with the angle of the sun and a wide-angle lens covers a wider area of the sky.

Even with a few pitfalls, the results achieved with a circular polarizing filter are definitely well worth the price of the filter. Using a polarizing filter will take your images to a whole new level.

The author is a landscape and nature photographer and offers her photography for purchase or viewing at http://www.naturesglory.ifp3.com