  We have developed an analytic model for generic image transfer using
microlens-coupled fibers to determine the telescope input beam speed that
optimizes the lenslet clear aperture and minimizes fiber focal-ratio
degradation. Assuming fibers are fed at f/3.5 by the lenslets, our study shows
that f/11 is the optimum telescope beam speed to feed a lenslet coupled to a
fiber with a 100um diameter core. These considerations are relevant for design
of high-efficiency, dedicated survey telescopes that employ lenslet-coupled
fiber systems.
