Optical Filters Quiz

Camera Accessory: Optical Filters

• Filters are camera accessories that modify the images recorded by a camera.

• Filters can be of a square or oblong shape and mounted in a holder accessory, or a glass or plastic disk in a metal or plastic ring frame that can be screwed into the front of or clipped onto the camera lens.

• Filters can make subtle or significant changes to the images recorded.

• There are different types of filters, including monochrome, colour conversion, color subtraction, contrast enhancement, polarizer, neutral density, cross, and diffusion filters.

• Clear filters are used to protect the front of a lens, while UV filters are used to block invisible ultraviolet light.

• Appropriate colour conversion filters compensate for the effects of lighting not balanced for the film stock's rated colour temperature.

• Coloured filters are commonly used in black and white photography to alter the effect of different colours in the scene, changing contrast recorded in black and white of the different colours.

• Polarizing filters filter out light with a particular direction of polarization, reducing oblique reflections from non-metallic surfaces.

• Neutral density filters attenuate light of all colours equally, allowing for a longer exposure or larger aperture than otherwise required for correct exposure in the prevailing light conditions.

• Diffusion filters soften subjects and generate a dreamy haze, reducing contrast.

• Close-up lenses are used for close-up and macro photography, and work in the same way as spectacles used for reading.

• High-quality filters are multi-coated, with multiple-layer optical coatings to reduce reflections.Overview of Camera Filter Sizes

• Camera filters come in different shapes and sizes.

• Filters are used to control the light entering the lens, correct colors, and add special effects.

• Circular filters have a diameter ranging from 43mm to 127mm.

• The filter diameter is indicated on the lens face by the ⌀ symbol.

• Square filters are available in 2" × 2", 3" × 3", 4" × 4", 75 mm x 75 mm, 100 mm × 100 mm, and 130 mm wide sizes.

• Cokin System is a popular square filter system with three sizes of filters, A, P, and X Pro.

• Gel filters are common in square form and are used in lighting applications.

• Rectangular filters are used for graduated filters, and their width varies from 67 mm to 100 mm.

• Bayonet round filters are used by manufacturers such as Rollei and Hasselblad.

• Series filters were popular from the 1930s to the 1970s and were mounted between two rings.

• Series 9 filters are still being produced and sold today for motion picture cinematography.

• Different filter sizes and systems are usually not compatible with each other.