For a nonrotating black hole, how far from the singularity is the photon sphere compared with the Schwarzschild radius?

For a nonrotating black hole, the photon sphere is located 1.5 times the Schwarzschild radius from the singularity.

The photon sphere is a spherical region where light can travel in circular paths around a black hole. These orbits are unstable: a tiny disturbance sends the photon either inward toward the event horizon or outward into space. For a Schwarzschild black hole, its radius is three times the gravitational radius, which equals 1.5 Schwarzschild radii.

The photon sphere should not be confused with the black hole’s shadow. The shadow is a larger apparent dark area produced when light is captured or strongly deflected. A rotating black hole has more complicated photon trajectories because frame dragging shifts the paths depending on whether light travels with or against the spin.