The Focus Mask tool allows quick visual confirmation of the focus accuracy and, therefore, the image sharpness. The areas that are sharply focused will be displayed by the mask. When there is no area of the image in focus, however, the mask will not be displayed. The mask’s high-visibility is particularly convenient when working tethered, and especially when photographing some distance away from the computer screen. The Focus Mask is also a useful tool for deciding which images you need to work with prior to their adjustment.
Note that the Focus Mask is only compatible with RAW-based variants. Even though the Focus Mask remains unaffected by sharpening, it is influenced to a degree by both image resolution and noise levels. To counter this, the Focus Mask has a threshold setting located under the application preferences. By taking a test shot with the camera and lens at the expected settings and then adjusting the Threshold slider to suit, you can make a visual assessment of the required threshold on-screen (and in real-time when working tethered).
- In the main menu, select View -> Focus Mask and ensure it is toggled on (or if the Focus Mask shortcut has been added to the main toolbar, click on cross-shaped AF target icon. When active, the icon is displayed in orange). The mask will be displayed only on RAW-based variants in the viewer and browser.
- To remove the mask from images, select View -> Focus Mask and ensure it is toggled off (or click on the Focus mask icon a second time).
- The color, opacity, and the threshold of the mask can be altered by selecting Capture One -> Preferences… (Edit -> Preferences… on Windows).
- When only a small area of sharpness is displayed and a larger area (i.e., a less discerning response to sharpness) is required, drag the Threshold slider to the left.
- When the assessment of sharpness is more critical, increase the Threshold by dragging the slider to the right.
- Sharpness should always be confirmed using the Focus tool at 100% or by removing the mask and checking on-screen at 100% magnification.