  The temperature and frequency dependences of the conductivity are derived
from optical reflection and transmission measurements of electron doped
BaFe$_2$As$_2$ crystals and films. The data is consistent with gap nodes or
possibly a very small gap in the crossover region between these two
possibilities. This can arise when one of the several pockets known to exist in
these systems has extended s-wave gap symmetry with an anisotropic piece
canceling or nearly so the isotropic part in some momentum direction.
Alternatively, a node can be lifted by impurity scattering which reduces
anisotropy. We find that the smaller gap on the hole pocket at the $\Gamma$
point in the Brillouin zone is isotropic s-wave while the electron pocket at
the $M$ point has a larger gap which is anisotropic and falls in the crossover
region.
