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Dear all,

I find that there is someting I have not 
understood regarding lateral resolution in our confocal (Zeiss 510 meta).
As I understand it, lateral resolution should be 
dependent on excitation wavelength and NA solely. 
But what is the case if we open the pinhole a bit 
above 1 AU? For some (admittedly special) samples, we use up to about 4AU.
As far as I understand it, on a 510, using a 40x 
1.3 objective, 532ex/575em, zoom 1, the pinhole 
is 300um, and the object-side projected pinhole 
diameter is then about 2,2um. As the PMT detector 
itself is not position-sensitive any light within 
this 2.2um circle in the focal plane would be 
detected. The practical resolution would then be 
determined by the laser spot size (?).
Using the zeiss "optimal frame size" calculator 
for nyqvist sampling on the above setting gives 
me 2048*2048 pixels, which is the max available, 
maybe it would calculate an even higher nunber of 
pixels if the option was available. 2048*2048 
gives me a pixel size of 0.11*0.11 um , which to 
me seems small in relation to the spot size of the laser.
Is this reasoning correct, or where am I wrong?

Thanks in advance,

Jan Grawé
Cell Analysis Core Facility
Rudbecklaboratoriet/C5
Dag hammarskjölds väg 20
SE-75185 Uppsala
SWEDEN

Phone: +(0)18-4714657
Cell:   +(0)70-2577874
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www.rudbeck.uu.se/cellanalys