Guys findings are similiar to what I get using a 100X 1.4 Nikon on my
MRC600. Looking at a power spectrum analysis, we get 200nm lateral and
600nm axial at which point the signal falls into the noise of the system.
 
The Rayleigh limit for 1.4 n.a., 520nm light, and r.i.=1.515 is 0.227 um.
The theoretical limit is 0.054 nm lateral and 0.095 nm axial. In general
most people consider an axial/lateral ratio of 2.0 to be pretty good.
 
________________________________________________________________________________
 
 
Paul Goodwin
Image Analysis Lab
FHCRC, Seattle, WA
 
On Mon, 12 Feb 1996, Guy Cox wrote:
 
> >Dear Guy Cox (and to others who have measured this):
> >   what is your FWHM in the x, y, and particularly z-dimension using
> >100 nm beads and the mentioned objective (63x, 1.4 N.A.). I recently
> >measured this on our Zeiss LSM410 and was disappointed: 1.8 um FWHM
> >with a Zeiss Plan-Neofluar (40X N.A. 1.3 oil) in the z-axis. In the y
> >x dimension the FWHM was as expected diffraction limited.
>
>
> I'd be pretty disappointed by this figure too.  Measurements I
> got, with the abovementioned x63 NA 1.4 lens, on a Bio-Rad MRC600,
> were lateral FWHM 250nm, axial 600nm.  I thought these were a little
> disappointing, actually. I wonder if you have a refractive index
> mismatch problem?
>
>                                                 Guy Cox
>