  We develop a new photometry algorithm that is optimized for $Spitzer$ time
series in crowded fields and that is particularly adapted to faint and/or
heavily blended targets. We apply this to the 170 targets from the 2015
$Spitzer$ microlensing campaign and present the results of three variants of
this algorithm in an online catalog. We present detailed accounts of the
application of this algorithm to two difficult cases, one very faint and the
other very crowded. Several of $Spitzer$'s instrumental characteristics that
drive the specific features of this algorithm are shared by $Kepler$ and
$WFIRST$, implying that these features may prove to be a useful starting point
for algorithms designed for microlensing campaigns by these other missions.
