  We demonstrate that the location of a stable photon sphere (PS) in a compact
object is not always an edge such as the inner boundary of a black hole shadow,
whereas the location of an unstable PS is known to be the shadow edge notably
in the Schwarzschild black hole. If a static spherically symmetric (SSS)
spacetime has the stable outermost PS, the spacetime cannot be asymptotically
flat. A nondivergent deflection is caused for a photon traveling around a
stable PS, though a logarithmic divergent behavior is known to appear in most
of SSS compact objects with an unstable photon sphere. The reason for the
nondivergence is that the closest approach of a photon is prohibited in the
immediate vicinity of the stable PS when the photon is emitted from a source
(or reaches a receiver) distant from a lens object. The finite gap size depends
on the receiver and source distances from the lens as well as the lens
parameters. The mild deflection angle of light can be approximated by an
arcsine function. A class of SSS solutions in Weyl gravity exemplify the
nondivergent deflection near the stable outer PS.
