Ambiguities in fits of binary lens galactic microlensing events

For observed galactic microlensing events only one fit is usually presented, though, especially for a binary lens, several fits may be possible. This has been shown for the MACHO LMC#1 event (Dominik & Hirshfeld 1996). Here I discuss the strong binary lens events OGLE#7 and DUO#2. It is shown that several models with a large variety of parameters are in accordance with the photometric data. For most of the fits, 1-sigma-bounds on the fit parameters are given. The variation of the parameters within the bounds is in some cases considerable. It is likely that other binary lens systems which will occur will have properties similar to the discussed events.