  We simulate the spin-1/2 Ising model and the Blume-Capel model at various
values of the parameter D on the simple cubic lattice. We perform a finite size
scaling study of lattices of a linear size up to L=360 to obtain accurate
estimates for critical exponents. We focus on values of D, where the amplitudes
of leading corrections are small. Furthermore we employ improved observables
that have a small amplitude of the leading correction. We obtain
nu=0.63002(10), eta=0.03627(10) and omega=0.832(6). We compare our results with
those obtained from previous Monte Carlo simulations and high temperature
series expansions of lattice models, by using field theoretic methods and
experiments.
