  It has been shown that a flux--weighted full width at half maximum timescale
of a microlensing event can be used in an unbiased estimator of the optical
depth. For the first time, this allows a physical parameter to be easily
estimated from pixel microlensing data. We derive analytic expressions for the
observed rate of pixel lensing events as a function of the full width at half
maximum timescale. This contrasts work in the literature which express rates in
terms of an ``event duration'' or Einstein time, which require knowledge of the
magnification, which is difficult to determine in a pixel event. The full width
at half maximum is the most directly measured timescale. We apply these results
to possible pixel lensing surveys, using HST for M87, and CFHT for M31. We
predict M87 microlensing rates for the HST Advanced Camera and for NGST, and
demonstrate that one will be able to probe the stellar IMF. Next, we describe a
new method by which a crude measurement of the magnification can be made in the
regime of magnifications A~10-100. This in turn gives a crude measurement of
the Einstein time. This program requires good photometry and sampling in the
low magnification tails of an event, but is feasible with today's technology.
