A Circular Polarizer has the same effect as a Polarizer and is used on cameras with beam splitting metering systems commonly found on auto focus SLR's (for most 35mm auto-focus cameras see your camera manual).
Area of sky most effectively polarized with a Circular Polarizer: Point your index finger at the sun. With your thumb extended at a right angle (90°), rotate it around the axis of the index finger. It will point out the band of deepest blue from horizon to horizon.
Essential general-use outdoor color filter
Produces deeper skies and minimizes reflections in black and white and color photography
Combine a Polarizer with a Red 25 for incredibly dramatic black and white landscapes
Can be rotated to achieve desired effect
Use the Tiffen Polarizer with the enhancing filter for more dramatic effects
This is the construction of a type of filter. The type of process used to create a filter can affect its price. Filters can be constructed out of regular glass that sandwiches a coloured gel in between or in high-end filters, raw elements are added to the molten optical glass so there is no risk of uneven colour or fading.
This is the size of a front lens cap. Standard sizes for snap-on lens caps include: 27mm, 28mm, 30mm, 34mm, 37mm, 39mm, 40.5mm, 43mm, 46mm, 49mm, 52mm, 55mm, 58mm, 62mm, 67mm, 72mm, 77mm, 82mm and 86mm.
When placed in the optical path, many filters block a certain amount of light from reaching the lens. Filter factor relates to how much exposure compensation is required in order to adjust for this. Most cameras have TTL metering and will be able to do this automatically.