Lyric Masked Sharpen
The Lyric Masked Sharpen filter applies a standard Unsharp Mask sharpening to the clip. It can be used in conjunction with matte filters and other alpha-channel sources to allow its effect to be masked to certain areas within the clip, and it can also be applied to specific image channels to achieve image-correction and other stylistic effects.
The Lyric Sharpen filter is a full implementation of the Unsharp Mask algorithm. Final Cut's built-in Unsharp Mask filter does not correctly process the dark sides of edges within the image and so does not produce a complete sharpening. You should use the Lyric Sharpen filter in favor of the built-in filter in all cases, not just when masked or channel sharpening is desired.
The above example shows the foreground object under high-radius sharpening to increase local contrast, while the background remains unchanged. The Lyric Color Matte was used to select the red petals as a filter mask for the foreground.
The Masked Sharpen filter includes a set of effect controls that are common across all Lyric effect filters. For a detailed description of these controls, please see the Common Effect Controls documentation.
For background information on mattes and masks and their uses in Final Cut, please refer to the Lyric Matte Primer.
The Amount slider increase the amount of sharpening by increasing the contrast across edge boundaries. Radius sets the width of the region across the boundaries that are adjusted, increasing it will increase the effect up to a point at which halos will start to appear within the radius distance. This halo effect can cause color distortion across the edges, so a common technique for achieving high sharpending levels is to apply it to just the luminance channel, which you can do by selecting Luminance mode in the Apply To menu. Increasing Radius too much can also prevent fine details from being sharpened as they are lost within the edge radius.
Threshold specifies how defined the edges have to be in order to have the sharpening effect applied. Higher values require higher brightness differences across edge boundaries for them to be included in the sharpening. This control is commonly used to avoid unwanted sharpening of detail such as video noise; you should set it high enough so that only the desired edges are sharpened.
The Effect Controls section is a set of common controls that are documented on the Common Effect Controls page. They can be used to achieve masked and other specialized filter effects.