  We consider N=2 SU(2) Seiberg-Witten duality theory for models with N_f=2 and
N_f=3 quark flavors. We investigate arbitrary large bare mass ratios between
the two or three quarks at the singular points. For N_f=2 we explore large bare
mass ratios corresponding to a singularity in the strong coupling region. For
N_f=3 we determine the location of both strong and weak coupling singularities
that produce specific large bare mass ratios.
