Figure 16.48.
Example for the “Lens Distortion” filter
Original image
“Lens Distortion” applied
This filter lets you simulate but also correct the typical distortion
effect introduced in photo images by the glasses contained in the camera
lenses.
4.8.2.
Activate the filter
This filter is found in the image window menu under
Filters → Distorts → Lens Distortion.
4.8.3.
Options
Figure 16.49.
“Lens Distortion” options
The allowed range of all options is from -100.0 to 100.0.
Preview
The result of your settings will appear in the Preview without
affecting the image until you click on OK.
Main
The amount of spherical correction to introduce. Positive values
make the image convex while negative ones make it concave. The
whole effect is similar to wrapping the image inside or outside a
sphere.
Figure 16.50.
Example result of Main option
-100.0
0.0
+100.0
Edge
Specifies the amount of additional spherical correction at image
edges.
Figure 16.51.
Example result of Edge option (Main set to 50.0)
-60.0
0.0
+60.0
Zoom
Specifies the amount of the image enlargement or reduction caused
by the hypothetical lens.
Figure 16.52.
Example result of Zoom option
-100.0
0.0
+100.0
Brighten
The amount of the “vignetting” effect: the brightness
decrease/increase due to the lens curvature that produces a
different light absorption.
The Main or Edge options
must be non zero for this option to produce noticeable results.
Figure 16.53.
Example result of Brigthen option (Main set to 75.0)
-25.0
0.0
+25.0
X shift; Y shift
These two options specify the shift of the image produced by not
perfectly centered pairs of lenses.
As above this option produces visible results only if the
Main or Edge options
are non zero.
Figure 16.54.
Example result of X shift option (Main set to 70.0)
-100.0
0.0
+100.0
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