  The Hubble Space Telescope (HST)/Space Telescope Imaging Spectrograph (STIS)
contains the only currently operating coronagraph in space that is not trained
on the Sun. In an era of extreme--adaptive-optics--fed coronagraphs, and with
the possibility of future space-based coronagraphs, we re-evaluate the contrast
performance of the STIS CCD camera. The 50CORON aperture consists of a series
of occulting wedges and bars, including the recently commissioned BAR5
occulter. We discuss the latest procedures in obtaining high contrast imaging
of circumstellar disks and faint point sources with STIS. For the first time,
we develop a noise model for the coronagraph, including systematic noise due to
speckles, which can be used to predict the performance of future coronagraphic
observations. Further, we present results from a recent calibration program
that demonstrates better than $10^{-6}$ point-source contrast at 0.6", ranging
to $3\times10^{-5}$ point-source contrast at 0.25". These results are obtained
by a combination of sub-pixel grid dithers, multiple spacecraft orientations,
and post-processing techniques. Some of these same techniques will be employed
by future space-based coronagraphic missions. We discuss the unique aspects of
STIS coronagraphy relative to ground-based adaptive-optics--fed coronagraphs.
