Library for Canon FD Lenses
Fisheye lenses and it Optical Properties
Originally designed for scientific studies, the 7.5mm fisheye was once called the full sky lens. It was primarily used for astrophotography and astronomical observations. Today, however, the fisheye lens is widely used by professional photographers or researchers when special effects are desired. Imaginative use of the various optical characteristic of a fisheye lens can create a world of mystery from the most conventional subject matter.
Looking through the viewfinder of a camera equipped with a 7.5mm fisheye lens can be an experience. You see everything from the ground at your feet (and perhaps your feet, too), to the sky overhead and virtually everything to your right and left within a radius of 180°. The image in the viewfinder is circular in the middle of the picture frame and that's the way it will be reproduced on film. The fisheye lens' view is like that of a fish looking through the water to the surface as shown in the illustration below. Because of the refraction between water and air the fish has a tremendously wide angle of view. The front element of a fisheye lens has an extreme amount of curvature which accounts for its 180° vision.
The large, concave lens in front covers the subject area and then bends the light into approximately a 90° cone. The convex lens at the rear then forms the image on film. The same degree of coverage in a conventionally designed lens would require a much larger image area. Instead, with this lens, a limited circular image is projected on film.
The Fisheye 7.5mm lens is able to include within its 180-degree field of view subject to either side of the the directly in the foreground. As seen by a fish in the sea - a viewing range of 180 ° is possible.
Due to the small image area, straight lines are rendered in a barrel or arch shape. Using the equidistant projection method, this circular image fisheye with its 7.5mm focal length compresses the 180° field into a 23mm diameter circle.
- Tips: The fisheye lens bends straight lines, whether vertical or horizontal.
- Straight Lines at the center of the image show little or no distortion. If you want to emphasize the special effects of the fisheye using familiar subjects, choose a scene with a predominance of straight lines particularly away from the center of the subject area. In most cases, may not be a suitable lens for portraiture unless certain special effect is desirable, if persist to do so, least distortion is also around the center
- Curved or rounded objects may exhibit some fisheye effect in the photograph, but often not to a marked degree.
- While there is no focusing mechanism on the 7.5mm fisheye, it can be used effectively for close focusing.
- The extremely short 7.5mm focal length and f/5.6 aperture combine to provide tremendous depth of field.
- It is a lens that covers a field of view of 180°. Check the finder for the intrusion of unwanted objects such as your feet, tripod legs or even part of the camera strap.
- Its extremely wide angle of view doesn't permit the use of a lens hood hence it cannot be protected from the direct rays of the sun or bright backlight.
Fisheyes are different from ultra-wide angle lenses, since their most obvious feature is perspective distortion that caused the bending of straight lines, especially those near the edges of the frame. Other factors are the exceptional depth of field and stretched out perspective. interchangeable lens you use.
Fisheye 7.5mm f/5.6 Lens
This lens is one of the most compact circular-image fisheye lenses available today... Focusing is unnecessary because of the inherently great depth-of-field of this focal length.
Since it is of retrofocus design, it does not require mirror lockup and thus can be used on virtually all SLR models in the Canon line up. It is an ideal lens for the photographer seeking dramatic effects as well as the scientist or technical photographer needing a hemispherical lens for special observations.
This lens has a 180 °angle of view in a 23mm diameter circle. All lines with the exception of those passing through the lens' horizontal and vertical center follow the natural curve of the circular image. Its retrofocus design eliminates the need to lock the camera's mirror up. This allows uninterrupted viewing and is especially valuable given the unusual perspective inherent in this lens. Focusing is unnecessary due to its tremendous depth of field consequently a focusing mechanism is not incorporated. With a close minimum focusing distance of only 35cm. Using a unique rotating turret, the Fisheye 7.5mm lens features six built-in filters, Sky, Y3, 01, R1, CCA4 and CCB4. Its extremely wide angle of view does not permit the use of a lens hood. Manually-operated diaphragm with stopped-down metering.
Focal length: 7.5mm
Aperture ratio: 1:5.6
Lens construction: 8 groups, 11 elements
Coating: S.S.C. (super spectra coating)
Angles of view: 23mm diameter circle at center of picture, 180 degrees
Distance scale: None
Minimum aperture: f/22
Filters: Built-in type (revolving, with click stops.) Six filters: SKY, Y3, 01, R1; CCA4, CCB4
Lens Hood: Not available
Function: Auto aperture, full aperture metering (AE operation when used with all Canon AE SLR cameras.
Length x max. diameter: 62mm x 72mm
Older Version: Canon Lens Fisheye 7.5mm f/5.6 S.S.C.
A circular fisheye which projects a delivers a different effect than the 15mm full-frame fisheye and other wide-angle lenses. Click Here to the dedicated page
Canon EOS SLRs | Canon EF lens Resources
| Back | Main Index Page of Canon FD lenses
| Back | Main Index Page of Canon A & T Series SLR Models
| Message Board | for your Canon A-Series SLR camera(s)
| Message Board | for your Canon T-Series SLR camera(s)
| Message Board | for your Canon T90 SLR camera
| Message Board | for your Canon F-1(n) SLR camera
| Message Board | for your New Canon F-1 SLR camera
| Message Board | for your Canon Optics in a shared environment
| Message Board | Specifically for Dispose or Looking for Canon Photographic Equipment
about this Site
Home - Photography in Malaysia
Copyright © 2000. leofoo ®. MIR Web Development Team.
Site Maintenance Editors: Kaipin, Terry Carraway, Gerry, Winston, Tom & IRwin (Dr Strangelove); Credit: Richard Yeow, general manager of Canon Marketing for his continual support; Mr. Philip Chong, who volunteered to be a Maintainer of this site; Mr. Vincent Thian, an AP (Associated Press) photographer for contributing some of the great images appeared in this site; Mr. CYLeow, photo-editor of The Star newspaper for some of his images used; my nephew EEWynFoo for helping so much of the tedious scanning works. And TO ALL THE CANON GURUS: Thank you for helping so much with the input of so much of invaluable information at the various Canon Message Boards. Site created 'unfortunately again with a PowerMac.