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
[table caption=”orthographic angles” width=”500″ colwidth=”50|50|50|50″ colalign=”center|center|center|center”]
weak,medium,strong,max
66,90,120,180
[/table]
![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