Let f (n, ) be the maximum integer such that every set of n points in the plane with at most collinear contains a subset of f (n, ) points with no three collinear. First we proveΩ( n log n), which implies all previously known lower bounds on f (n, ) and improves them when is not fixed. A more general problem is to consider subsets with at most k collinear points in a point set with at most collinear. We also prove analogous results in this setting.