Penflex CPL Filter 52mm

Penflex Circular Polarizers (CPL) are manufactured from Glass with Polarizing materials incorporated. The rings are metal, and feature a male thread which screws into the filter, and a female thread on front to accept lens hoods, other filters, or accessories. Once attached to a lens, the front ring of the polarizer rotates and may be adjusted for maximum effect. This is typically done by looking through the viewfinder while turning the front ring on the filter.

Slim Design. Designed with a slim design metal ring. The thickness of the metal ring projects only 6.5 mm past the front of the lens. Knirled front edes provide a better grip. Total thickness of the filter is only 8.2 mm.

A polarizing filter is placed in front of the camera lens in photography in order to darken skies, manage reflections, or suppress glare from the surface of lakes or the sea. Since reflections (and sky-light) tend to be at least partially linearly-polarized, a linear polarizer can be used to change the balance of the light in the photograph. The rotational orientation of the filter is adjusted for the preferred artistic effect. For modern cameras, a circular polarizer (CPL) is typically used; this comprises firstly a linear polarizer which performs the artistic function just described, followed by a quarter-wave plate which further filters the now-linearly polarized light into circularly-polarised light before entering the camera. This additional step avoids problems with auto-focus and light-metering sensors within some cameras, which otherwise may not function reliably with a simple linear polariser.

The Above image shows a picture taken with a polarizer, left, and without, right.

The image above demonstrates how a polarizer can nearly elimate reflections on water.  Picture taken with a polarizer, right, and without, left

Reflections are almost completely eliminated in this image. Polarizer used on the image on the right.

Images used under the Creative Commons License, Unaltered

License May Be Found Here: http://creativecommons.org/licenses/by-sa/3.0/legalcode