Helicon Filter Help - Preview window

Distortions Tab

This tab offers you a full set of controls to compensate for radial and perspective distortions as well as vignetting.

Please note that some slow filters are ignored on this tab for faster preview (Noise reduction, Sharpening, Chromatic aberration, Retouching).

To apply all filters and see the final result please switch to the Save tab. If you like the result, you can save it and process the next image. If you don't, you can always switch back to the filter, fine tune the settings and get updated result.

The program remembers the settings for each file you processed. So when you open a file again, the program recalls the most recent settings for this file. You can also save the file settings manually (Menu->Settings->File Settings).

Controls

The Load Settings select box lets you choose one of the predefined settings for this tab. You can also save your current settings for future use.

The Enable distortions checkbox turns the whole tab on or off.

The Barrel/pincushion slider compensates radial/spherical distortions by stretching the corners.

The Horizontal perspective slider squeezes left or right side of the image.

The Vertical perspective slider squeezes a top or a bottom of the image.

The Squeeze/stretch slider squeezes or stretches the image.

The Auto crop checkbox stretches the image proportionally so that the whole image is filled. If you do not like how this function works you can define an area on the Crop&Resize tab later.

The Grid checkbox adds a grid to the image to facilitate a proper alignment of the image, especially barrel and perspective distortions.

The Rotate slider lets you turn the image clockwise or counterclockwise.

The Skew slider defines the shift of the upper part of the image.

The Bend slider lets you straighten the horizon by lifting/sinking image sides relatively to the its center.

The Vignetting slider defines a brightness compensation in the image's corners.

The Curve steepness slider defines a brightness compensation degree along the radius. High values result in correction only in the corners, low values let you also correct other parts of the image.

The Compare mode checkbox emphasizes the vignetting effect by adding mirror images from each side of the image. You can find the optimal parameters in this mode easier.

Original image, usual mode	Original image, compare mode

Simple mode

If you prefer an easy and straightforward interface, you can switch to simple mode. Go to main menu of Helicon Filter and select "View\Simple preview mode" command. Or press button on the toolbar.

Hints and Tips

The less you change the image, the better
Switch on the Grid for distortion correction.
Switch on the Compare mode for vignetting correction.

Recommended workflow

General workflow

Switch on the Grid and check if the image has distortions. Correct distortions if needed.
Switch on the Compare mode to check if the image has vignetting. Correct vignetting if needed.

To show or hide Help panel of Helicon Filter use button from the toolbar or View->Help panel command in the main menu.