  We show that reformulating the Direct State Tomography (DST) protocol in
terms of projections into a set of non-orthogonal bases one can perform an
accuracy analysis of DST in a similar way as in the standard projection-based
reconstruction schemes. i.e. in terms of the Hilbert-Schmidt distance between
estimated and true states. This allows us to determine the estimation error for
any measurement strength, including the weak measurement case, and to obtain an
explicit analytic form for the average minimum square errors.
