Wide-angle lens

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Image:Canon 17-40 f4 L lens.jpg In photography and cinematography, a wide-angle lens is a lens whose focal length is shorter than the focal length of a normal lens. For a 35 mm camera with a 36 mm by 24 mm format, the normal lens is 50 mm. A lens of focal length 35 mm or less is considered wide-angle.

In addition to giving a wider angle of view, the resulting image can also have perspective distortion.

Common wide-angle lenses for a 35 mm camera are 35, 28, 24, 20, 17 and 14 mm. These lenses will give a rectilinear projection.

Extreme wide-angle lenses normally do not give a geometric projection, and are called fisheye lenses. Common focal lengths for a 35 mm camera are 6 to 8 mm (will give a circular image), and 15 or 16 mm (will give a curvilinear, full-frame, image).

Projection of these lenses can be described by the shape of the projection area (for geometric projection). Normal (perfect) lenses use rectangles, (perfect) fish eyes use parts of spheres or cylinders.

There is no distortion when imaging and projection are done by lenses with the same projection theme.

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