CornerFix options

CornerFix allows a number of options to be set:

General options

1. Verbose. If Verbose is selected, data on the contents of the image file and the application's internal operations are output to the status display in CornerFix for Windows' screen display.
2. Multiple Equation. By default, CornerFix evaluates only the most commonly used equation for devignetting. However, CornerFix is preprogrammed with an additional 20 equations. If this option is checked, CornerFix evaluates the quality of correction for each one in turn, and selects the best one. Best is defined as the simplest equation that delivers within 2% of as good a result as the absolute best equation.
3. Warning: Enabling Multiple Equation can take a long time to complete.
4. Warning: Enabling both Multiple Equation and Verbose is not recommended.
5. Illuminant Compensation. By default, CornerFix compensates for variations in illuminant. However, this is only useful if the variation is linear across the field. In most situations, illuminant compensation is best left on. It will not negatively impact on the analysis of a image with flat lighting, and will help in most situations where less than perfect lighting used.
6. Bidirectional Correction. As of version 1.2 of CornerFix, lens profiles are generated in such as to avoid any overcompensation anywhere in the image. Previous version tolerated some overcompensation in the corners if the image was, on average, better compensated as a result. Enabling bidirectional correction reverts CornerFix the previous profile generation algorithm. Note: In order to correct for “red corners” as a result of incorrect in-camera correction, you must enable Bidirectional Correction

Tweaking the Image

There are two tweaks that you can apply to the image conversion process. Note that these settings impact only on the image correction process – these tweaks do not have any effect on the generation of profiles:

1. Luminance and Chroma strength. By default, CornerFix compensates 100% for variation both in “brightness” (luma) and Chroma (color). However, you can choose to vary these strengths via the “Image Options” dialog. This can allow you to avoid over-compensating an image, and also can allow you to avoid an “over clinical” look to your corrected images. The same effects as previous versions of CornerFix can be achieved by setting both Luminance and Chroma to 1.0, which are the default settings. This gives 100% correction of both Luminance and Chroma vignetting.
2. Anti-aliasing. Adjusted images can under rare circumstances display compression artifacts which are visible as concentric circles on the corrected image. If this occurs, the anti-alias setting can be increased to reduce these artifacts. Note that increasing the anti-aliasing strength also increases apparent noise. A setting of 0 gives equivalent performance to CornerFix 0.9.0.2 and 0.9.0.3, while a setting of 1 gives equivalent performance to 0.9.0.4. Unless there are visible artifacts in your corrected image, you should leave this set to 0, which is the default setting

The Leica MakerNotes

The Leica MakerNotes options are discussed on this page.