Digital Photography Tip Number 5....Use a circular polarizer filter
Tip #5) Use A Circular Polarizer Filter.... Polarizer filters really improve photos. They reduce the glare, or shinyness from water and surfaces, they reduce reflections on windows, they reduce the haze in the air, they make for richer colors in photos and they really improve the blue of the sky.
Great Deals On Circular Polarizer Filters!
To get the best effect from a polarizer filter you should try and shoot the photos in a direction that is 90 degrees from the sun. So the best use of the polarizer is when the sun is on the left or right side of you.
During cloudy days, the polarizer still helps to reduce the glare on surfaces, and reduce the haze in the air. Polarizers do reduce the light entering the camera, so make sure your shutter speed is still fast enough, at least 1/60th of a second, so you don't get blurred images. You could either increase the ISO setting or open up the aperture to let more light in and increase the shutter speed. Depending if you have a built-in image stabilizer, or have steady hands, a shutter speed of 1/60th of a second can work for handheld shots, but it would be best to have the shutter speed slightly higher for handheld shots, like 1/125th of a second.
Polarizer filters can also be used as neutral density filters. Neutral density filters are just grayish filters that don't effect the colors of a photo, they just reduce the amount of light entering the camera. You might want this reduction in light, so you can have longer exposure times in bright conditions to make the water in waterfalls and rivers, look blurred and flowing. Also, you might want to use your polarizer filter as a neutral density filter to get less depth-of-field(focus) in your photos. If it is too bright to use a large aperture for short depth-of-field(focus), then you can use your polarizer to get a bigger aperture and less depth-of-field(focus).