Lens hood
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In photography, a lens hood or lens shade is a device used on the end of a lens to block the sun or other light source in order to prevent glare and lens flare.[1]
The geometry of the lens hood can vary from a plain cylindrical or conical section (much like a lamp shade) to a more complex cut sometimes called a petal, tulip or flower hood, which produce a reasonable good shade without blocking the field of view of the lens and thus producing vignetting. Properly petal shaped lens hoods produce more shade than normal lens hoods with the same end diameter. Square lens hoods may be even better.[citation needed]
Lens hoods are more prominent in long focus lenses because the field of view has a smaller viewing angle than of wide-angle lenses. For wide angle lenses, the length of the hood (away from the end of the lens) cannot be as long as those for telephoto lenses because of the viewing angle.
Lens hoods are often designed to fit onto the matching lens facing either forward, for normal use, or backwards, so that the hood may be stored with the lens without occupying much additional space. Some lens hoods are flexible and collapse for storage.
In addition, they offer some physical protection for the lens due to the hood extending farther than the lens itself.[2]
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A conical petal lens hood used on the Canon EF 70-200mm lens. Note that from this angle no part of the glass lens surface is visible, as the line of sight is blocked by the lens hood. -
Canon lens without and with a conical petal lens hood -
Praktica camera – lens with a conical collapsable rubber lens hood
See also
- Lens cover
- Matte box – similar, adjustable device used in still photography and video
- Barn doors – similar device used for stage lights
References
- ^ van Walree, Paul: Lens hoods, http://toothwalker.org/optics/lenshood.html
- ^ Harmer, Jim, "What does a lens hood do?", Improve Photography, 15 Jun 2011
External links
- DIY Lens Hood How to make an effective hood for your lens
- lenshoods.net (»Free printable cardboard lens hoods«)
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