Various types of fisheye lenses are available.
Here a short overview:
[table class=”table table-striped”]Type,gnomonic,stereographic,F-Theta,equal area,orthographic
lens class,wide angle,Fisheye,Fisheye,Fisheye,Fisheye
mapping function, ,
,
,
,
normalized mapping function ,
,
,
,
,
meridional scaling ,
,
,
,
,
sagittal scaling ,
,
,
,
,
effective scaling ,
,
,
,
,
N from ,2,1,0,-1,
Balance Deform. vs. Scaling ,
,0,-2,
,2
Curvature ,0,
,
,
,-1
Deformation ,
,
,
,
,
maintains,-,angles,angular distances,areas,planar illuminance
AOV ,<180°,<360°,>= 360°,360°,180°
,54°,94°,115°,94°,66°
,75°,131°,159°,131°,90°
,102°,180°,217°,180°,120°
[/table]
Source of the various angles and formulae: wikipedia
Here the angle is measured in Radians !
F-Theta lenses are also called “equidistant“, “linear scaled“, “äquidistant” or “angular”
sterographic lenses are also called “ conform“or “ winkeltreu”
orthographic lenses are also called” hemispherical“or “orthographisch“
For details see:
equal area
F-Theta
gnomonic
orthographic
stereographic