F-Theta lenses are a class of Fisheye lenses
F-Theta lenses are also called “equidistant“, “linear scaled“, “äquidistant” or “angular”
F-Theta lenses use an image mapping function of type


A non distortion F-Theta lens of 1.37mm focal length has an image circle of
mm =
mm
Therefor a f=3.17mm F-Theata lens with an image diameter for 180° of 4.15mm has a distortion of (4.15/4.3)-1 = 0.965-1 = -3.5%


Therefor a f=3.17mm F-Theata lens with an image diameter for 180° of 4.15mm has a distortion of (4.15/4.3)-1 = 0.965-1 = -3.5%
maintains angular distances
weak | medium | strong | max |
---|---|---|---|
115 | 159 | 217 | 360 and more |