orthographic lenses are a type of fisheye lenses
orthographic lenses are also called” hemispherical“or “orthographisch”
orthographic lenses use an image mapping function of type
maintains planar illuminance
| Type : orthographic | weak | medium | strong | max |
|---|---|---|---|---|
| angles | 66° | 90° | 120° | < 180° |
![hemi180[1]](https://www.optowiki.info/wp-content/uploads/2016/02/hemi1801.gif)
An orthographic / hemispherical fisheye, uses a parallel projection of a hemisphere onto a plane. The resulting image will obviously be circular. The widest view angle is 180 degrees. At +/-90 degrees extreme distortion will occur. Due to this heavy distortion it’s less often used than f-Theta / angular fisheye.
see:
fisheye types