Focus peaking
Technique
A camera display function that highlights sharp edges in the frame with a colored glow to assist manual focusing.
Focus peaking is a standard feature on mirrorless cameras and video-capable DSLRs. Set the color (red, white, yellow) and intensity. The more glow visible on the subject, the sharper it is. Ideal when using older lenses via an adapter without electronic coupling.
Tools that help with this: