  We present multiband optical/infrared photometry of V4580 Sgr, the optical
counterpart of the accretion-powered millisecond pulsar SAX J1808.4-3658, taken
during the 1998 X-ray outburst of the system. The optical flux is consistent
with emission from an X-ray-heated accretion disk. Self-consistent modeling of
the X-ray and optical emission during the outburst yields best-fit extinction
Av=0.68 and inclination cos(i)=0.65, assuming a distance of 2.5 kpc. The
allowed inclination range requires that the pulsar's stellar companion has
extremely low mass, 0.05-0.10 Msun. Some of the infrared observations are not
consistent with disk emission and are too bright to be from either the disk or
the companion, even in the presence of X-ray heating.
