Focal Shift controls the inner falloff of the brush tip shape within the cursor.
Press and hold the Focal Shift icon, then drag your pencil or finger up and down to adjust.
Focal Shift controls your brush tip's falloff of at a range of (-100 / 0 / +100).
The cursor has two circles. The space between these circles is the Focal Shift of the brush tip.
Positive values create more falloff of the brush tip shape between the cursor circles. Negative values create less falloff.
When an alpha is selected and DragRect Stroke is selected, the Focal Shift effect can be seen clearly at different Focal Shift slider settings.
Set Focal Shift to -100 to draw an alpha shape without falloff. This yields a crisp alpha shape.
ZBrush for iPad's Focal Shift and other draw-related settings work the same as in ZBrush desktop. Learn more in our external ZBrush Draw documentation.