>On the contrary though, it is not that difficult to acquire a PSF! There is
>software available on the market (e.g. Zeiss KS 400) that will basically
>allow beads much larger than the PSF itself

The problem with this approach is that the bead itself is usually
going to cause a lot of optical distortion, so unless you know the RI
of the bead and take it into account, the "distal" part of the PSF
may not be accurate.

Beat


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