Polarizing Filter is a polarizer for light source to be entered through the Lens, is based on dichroism and split up light into beams of different wavelengths and therefore absorbs complementary polarized light. We discussed the broader term Filer in Digital Photography. Polarizing Filter is a kind of special Optical Filter.
Basics of Polarizing Filter in Digital Photography
Most Polarizing Filter caps are technically manufactured for DSLR cameras. However, long zoom and Bridge cameras can have adopters to attach a Polarizing Filter. They may be used only for low-power light sources, because they will be destroyed due to overheating. These Polarizing Filers are actually more than just a protective transparent cover in front of the Lens.
Types of Polarizing Filter
Linear Polarizing Filter : Linear polarizing optical filters are usually based on the method developed by Edwin Herbert , which were made of macromolecular films that are stretched plastically in one direction. This stretching aligns the molecules in parallel. Diffused iodine is deposited on these chains and provides charge particles, which are movable in the direction of the chain of molecules, resulting in the absorption of parallel electromagnetic ray including visible light.
Circular Polarizing Filter : A circular Polarizing Filter consists of a linear polarizing filter, on the linear side, the incident light’s linearly polarized component is absorbed, other transmitted as circularly polarized light.
True Circular Polarizing Filter produce unpolarized light from circularly polarized light by chiral molecules layered over it.
Usages of Polarizing Filter
Image : The photo on the left was taken with a Polarizing Filter and the photo on the right without one.
Polarizing Filter removes the unwanted reflections from smooth, non-metallic surfaces, the color reproduction of green leaves and grasses becomes more natural. The blue of a cloudless sky is partially polarized. Using a polarizing filter, a large part of the bright sky are retained, so that the sky in the photo appears darker and thus more powerful in its color. White clouds become more distinct against the blue sky.