The Focus Mask tool is intended as a means of evaluating the sharpness of an image at the time of capture, particularly when working tethered. However, it is also useful when identifying and selecting properly focused images and attendant depth of field prior to adding sharpening.
- Press the Focus Mask icon. Sharp areas will be highlighted in a (default) green marking.
- Go to Capture One -> Preferences on macOS or Edit -> Preferences on Windows to adjust the Focus Mask settings.