Convex mirror
Diverges reflected rays off a real spherical surface of radius 2f, so it carries the spherical aberration a real one does.
Open in the canvas →In the real world
A convex (diverging) spherical mirror bulges toward the incoming light and spreads a reflected beam out rather than focusing it. It obeys the same mirror equation as a concave mirror, but with a negative focal length — object rays reflect as if diverging from a virtual focus behind the mirror, forming an upright, reduced virtual image. This is the geometry behind car passenger-side mirrors and wide-field security mirrors, both chosen for their expanded field of view rather than any focusing power.
In OpticalSetup
Identical implementation to the concave mirror — a real spherical surface of radius R = 2f, intersected and reflected analytically — just with the curvature the other way round, which is why the beam here spreads instead of converging. The aberration is present for the same reason and by the same mechanism; it simply matters less, because a diverging mirror is rarely asked to form an image.
Same caveats as the concave mirror: a 2D cross-section of a sphere rather than a full 3D surface, so only aberrations expressible in the meridional plane appear; no coating model, and so no wavelength- or angle-dependent reflectivity; and a mirror cannot be wider than its own sphere, so a very short focal length silently limits the aperture — the panel reports the size actually used.