Difference between revisions of "Fisheye lens"
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'''Fisheye lenses''' cover an extremely wide angle and render an image that is very distorted. This contrasts with most lenses, which are designed to minimise distortion. Fisheye lenses project severe distortion away from the image centre: only straight lines that pass through the centre will appear straight. The lenses come in two varieties: circular fisheye lenses, which project a circular 180 degree angle of view image within the film frame; and full-frame fisheye lenses, which fill the frame with 180 degree angle of view diagonally. | '''Fisheye lenses''' cover an extremely wide angle and render an image that is very distorted. This contrasts with most lenses, which are designed to minimise distortion. Fisheye lenses project severe distortion away from the image centre: only straight lines that pass through the centre will appear straight. The lenses come in two varieties: circular fisheye lenses, which project a circular 180 degree angle of view image within the film frame; and full-frame fisheye lenses, which fill the frame with 180 degree angle of view diagonally. | ||
Revision as of 17:17, 11 February 2012
Fisheye lenses cover an extremely wide angle and render an image that is very distorted. This contrasts with most lenses, which are designed to minimise distortion. Fisheye lenses project severe distortion away from the image centre: only straight lines that pass through the centre will appear straight. The lenses come in two varieties: circular fisheye lenses, which project a circular 180 degree angle of view image within the film frame; and full-frame fisheye lenses, which fill the frame with 180 degree angle of view diagonally.
Originally developed for metereological uses, their distortion limits their use in general photography.
Origin
The term "fisheye" comes from the similarly distorted view of the dry world when looking up from underwater. Because of light refraction when entering water, the image seen of the above water world when looking up from underwater is a circle with extreme distortion at the edges, just like a circular fisheye lens. This is the only way to project a 180 degree image onto a flat plane and the original use of these lenses was photographing cloud cover.
Full-frame fisheye lenses were developed for general photography but the extreme distortion is obvious. Jonathan Eastland comments that they are "...difficult to use with originality".[1]
The given focal length is only relevant for the image centre, towards the edges it is shorter still and the image compressed.
Notes
- ↑ Jonathan Eastland, The Leica R Compendium. Hove Books 1995 ISBN 1 897802 07 02 page 53
