  Hard semiexclusive processes provide an opportunity to design effective
currents to probe specific parton distributions and to probe in leading order
parton distributions that fully inclusive reactions probe only via higher order
corrections. High transverse momentum pion photoproduction is an example of a
such a process. We discuss the perturbative and soft processes that contribute,
and show how regions where perturbative processes dominate can give us the
parton structure information. Polarized initial states are needed to get
information on polarization distributions. Current polarization asymmetry data
is mostly in the soft region. However, with somewhat higher energy, determining
the polarized gluon distribution using hard pion photoproduction appears quite
feasible.
