On Thu, 6 Aug 1992, Jim Barrett wrote:
 
> I must be missing something here:
>
> >Only by throwing resolution away in the x-y plane. Confocal theory
> >does not necessarily allow for the z-res to equal x-y. It in fact predicts
> >a maximum of 2:1. Now by changin the gain:offset of the PMT it is possible
> >to acheive close to 1:1 but only at the extreme cost of loss of sensitivity
> >and dynamic range
>
> Why can't I interpolate in z to get the same aspect ratio?
> Isn't this the same as subsampling in x-y?
>
> However, when I interpolate 200 nm spheres I still wind up with elongated
> (in z) images.
>
> James R. Barrett	University of Virginia
> [log in to unmask]	Box 377, Biomedical Engineering, School of Medicine
> (804) 924-8520		Charlottesville, Va. 22908
 
James-
 
Perhaps you should describe your definition of "interpolating in z". I
don't see any way of gaining resolution in the z-axis without either
playing gain games or fully correcting the image for the PSF ala
Sedat/Agard. To remove the elongation, I could "smear" the x-y resolution
2-fold, thus reducing the x-y resolution. I can't sample z step sizes
smaller than 100 nm on the MRC-600 which is what I am already using. A 60x
1.4 n.a. objective on the MRC-600 with a zoom of 2 (max resolution/pixel)
has a point size of about 100nm on our system.
 
Paul