Aperture Sweet Spot
OpticsThe aperture at which a lens delivers peak sharpness across the frame, typically 2–3 stops below maximum aperture.
The aperture at which a lens delivers peak sharpness across the frame, typically 2–3 stops below maximum aperture. For APS-C the sweet spot is f/5.6–f/8 — the lower end applies to high-resolution bodies (40MP+) where diffraction becomes visible earlier. Stopping down further reduces sharpness due to diffraction.