Fisheye Lens Design

As a unique type of camera lens, fisheye lenses have some special properties when compared to other ordinary camera lenses. A fisheye lens should be an inverted telephoto lens due to the large FOV and short focal length. In order to direct all the light rays from an entire hemisphere into the aperture stop, fisheye lenses usually have more than one negative lens element in the front group to reduce the ray angles. The rear group of the fisheye lens needs to be positive to compensate for the total power of the lens. For accurately tracing the rays of a fisheye lens with large pupil aberration, the ray aiming algorithm needs to be turned on in the optical design software.

Shanghai Optics can optimize the entire process of designing and producing these fantastic lenses, which can help you receive high quality fisheye lenses in efficient ways.

To capture the entire hemisphere with a fisheye lens, strong barrel distortion must be introduced. The image close to the edge needs to be compressed compared to the center of the image. When using the traditional f-tanθ projection method to calculate the image height, fisheye lenses with a 180-degree FOV can exhibit -100% distortion at the edge of the image circle. The following figures show the f-tanθ distortion and the resulting image of a rectilinear object.