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 17.57. Example result of Main option

-100.0

0.0

+100.0

Specifies the amount of additional spherical correction at image edges.

Figure 17.58. Example result of Edge option (Main set to 50.0)

-60.0

0.0

+60.0

Specifies the amount of the image enlargement or reduction caused by the hypothetical lens.

Figure 17.59. Example result of Zoom option

-100.0

0.0

+100.0

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 17.60. Example result of the Brighten option (Main set to 75.0)

-25.0

0.0

+25.0

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 17.61. Example result of Shift X option (Main set to 70.0)

-100.0

0.0

+100.0

The result of this filter can be larger than the original image. With the default Adjust option, the layer will be automatically resized as necessary when the filter is applied. With the Clip option the result will be clipped to the layer boundary.