If I recall correctly, the photon sphere orbit is unstable, so there may not be a ton of photons there. "Unstable" in this sense means that photons in adjacent orbits tend to diverge away from the photon sphere orbit rather than toward it.

For Schwarzchild holes, the lowest circular orbit for massive objects is at 3 event horizons, which is above the photon sphere. There are unstable circular orbits down to 2 horizons. Black hole rotation reduces this altitude for prograde orbits asymptotically down to 1 horizon.