DISTORTION DIAGRAMS
Distortion describes the variation in the actual image height from the ideal
height, with the ideal image height calculated from the object height and the
reproduction scale. Relative distortion specifies the percentage variation of
the actual image height from the ideal. The image height 21.6mm is the
radial distance between a corner of the image field and the center of the
image (image format 24mm x 36mm). The graphical representation of the
effective distortion illustrates the actual course or curvature of horizontal
and vertical lines in the image plane.
Effective distortion
X'[mm]
12
9
6
3
0
0
3
6
[ % ]
Relative distortion
5
4
3
2
1
0
-1
-2
-3
-4
-5
0
3
6
9
12
15
18
Y'[mm]
9
12
15
18
21
Y'[mm]
VIGNETTING DIAGRAM
Vignetting describes the continuous reduction in the brightness of an image
(intensity) towards the edge of the image (edge shading, darkening of
corners of image). The graphic plots the percentage reduction in brightness
against the image height. At 100% no vignetting occurs.
5.6
2.8
1.4
[ % ]
100
80
60
40
20
0
0
3
6
Vignetting
9
12
15
18
21
Y'[mm]
EN
117