Certified Professional Photographer (CPP) Practice Exam

Polarizers can be categorized as linear or what other type?

1. Radial

2. Circular

3. Rectangular

4. Dynamic

The correct answer is: Circular

Polarizers are optical filters that allow light waves of a specific polarization to pass through while blocking other polarizations. They can primarily be categorized into two types: linear and circular. Linear polarizers transmit light waves that oscillate in a single plane. They are effective in reducing glare and reflections, which is particularly useful in photography to enhance colors and contrast. Circular polarizers, on the other hand, convert the linearly polarized light into circularly polarized light. This process allows for more versatility when used with certain camera systems, specifically those that rely on polarizing filters, such as modern digital cameras with autofocus systems and metering that can be affected by linear polarizers. Circular polarizers have two layers: one linear polarizing layer and a quarter-wave plate, which transforms the linear polarization into circular polarization. This distinction is what makes circular polarizers more effective in certain situations, particularly in reducing reflections from non-metallic surfaces and improving sky contrast while still allowing the camera's meter and autofocus system to function correctly. The other choices do not accurately represent the second category of polarizers. Radial, rectangular, and dynamic are not recognized classifications within the common polarizing filters used in photography. Understanding these categories helps photographers effectively choose the right filter for their specific