  We consider an observer who moves under the horizon of the Schwarzschild
black hole and absorbs a photon. There are two different situations when (i) a
photon comes from infinity, (ii) it is emitted by another observer under the
horizon (say, by a surface of a collapsing star). We analyze the frequency
change for absorption near the event horizon, in an intermediate region and
near the singularity and compare the results for both scenarios. Near the
singularity, in both scenarios infinite redshift (in the pure radial case) or
infinite blueshift are possible, depending on angular momenta of a photon and
an observer. The main difference between both scenarios manifests itself, if
photons from the star surface are emitted near the horizon and received in the
intermediate region or near the singularity by the observer with a nonzero
angular momentum.
