Focus Peaking
A display aid that outlines the highest-contrast edges in the live image, marking what is currently in focus.
In depth
Peaking detects local contrast, so it highlights whatever is sharpest — which is not the same as whatever is sharp enough. It is excellent for finding approximate focus quickly and unreliable for critical work at wide apertures, where the coloured fringe covers more depth than the true zone of sharpness. Magnification is the check.
Examples in practice
Red peaking outlines a model's eyelashes, confirming that focus sits on the eye rather than the cheekbone.