  We investigate the sensitivity of the differential cross section, recoil
nucleon polarization and the photon asymmetry to changes in the elementary
amplitude, medium modifications of the resonance $(S_{11},D_{13})$ masses, as
well as nuclear target effects. All calculations are performed within a
relativistic plane wave impulse approximation formalism resulting in analytical
expressions for all observables. The spin observables are shown to be unique
tools to study subtle effects that are not accessible by only looking at the
unpolarized differential cross section.
