Diffractive ϱ0 photo- and leptoproduction at high energies

We discuss the elastic photo- and leptoproduction of ϱ0-mesons from nucleons at Q2 ≲ 1 GeV2 as studied in recent experiments at HERA and FNAL. We find that the mass distribution of the measured π+π− pair is determined to a large extent by the two-pion contribution to the photon spectral function as given by the pion form factor. With rising Q2 the rate of diffractive events decreases and the π+π− mass distribution approaches a symmetric shape.