Re: Boosting bright field resolution with dichroic filters

Posted by Barbara Foster on
URL: http://confocal-microscopy-list.275.s1.nabble.com/Boosting-bright-field-resolution-with-dichroic-filters-tp7583983p7583996.html

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Unfortunately, the link didn't work.

Shouldn't it be 1.22?

Normally, you see it written as  0.6 only if it has been divided by 2NA.

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At 08:22 AM 7/13/2015, you wrote:

>*****
>To join, leave or search the confocal microscopy listserv, go to:
>http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
>Post images on http://www.imgur.com and include the link in your posting.
>*****
>
>Hi Steffen,
>Good question! The factor 0.61 comes from the calculation of the intensity
>distribution of light after the diffraction at circular apertures.
>Here is a link in german
>http://www.chemgapedia.de/vsengine/vlu/vsc/de/ph/14/ep/einfuehrung/wellenop
>tik/interferenz2e.vlu.html
>Best
>Jo
>
>ETH Zürich
>Joachim Hehl
>Staff Scientist
>ScopeM - Scientific Center for Optical and Electron Microscopy
>HPM E 14
>Otto-Stern-Weg 3
>CH-8093, Zurich
>Switzerland
>
>
>Web: www.lmc.ethz.ch
>Phone:     [phone]
>Natel:     [phone]
>Fax:       [phone]
>e-mail: Joachim.Hehl <mailto:[hidden email]>@scopem.ethz.ch
>
>
>
>
>
>
>
>
>On 7/13/15 11:26 AM, "Steffen Dietzel" <[hidden email]> wrote:
>
> >*****
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> >http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> >Post images on http://www.imgur.com and include the link in your posting.
> >*****
> >
> >Dear all,
> >
> >two questions, first about the formula:
> >
> >I thought 0.61*lambda/(NA)  (Rayleigh) would be the appropriate formula
> >for self-luminous objects (dark field, fluorescence) while for bright
> >field the fitting variant of the Abbe formula should be applied:
> >lambda/NA-obj for central illumination, lambda/2NA for NA-obj = NA cond
> >and, in general, lambda/(NA-obj + NA cond), provided that NA-obj is
> >equal or bigger than NA-cond.
> >
> >It seems though, that others are happy with 1.2*lambda/(NA-obj + NA
> >cond). Where does the 1.2 (or 2*0.6)  in a bright field situation come
> >from? Would that be the paper by Hopkins and Barham (1950), that Mike
> >was referring to? Because I have no hope of understanding this paper by
> >reading through during this life (Lots of formulas my biologist's brain
> >is not flexible enough to adjust for).
> >
> >Second:
> >Is there a good source for diatoms that can be stained with fluorescent
> >dyes and self-mounted, as George suggested? I have a few diatom slides
> >for teaching (Pleurosigma), but they came already mounted.
> >
> >Steffen
> >
> >>
> >>
> >> --
> >> ------------------------------------------------------------
> >> Steffen Dietzel, PD Dr. rer. nat
> >> Ludwig-Maximilians-Universität München
> >> Walter-Brendel-Zentrum für experimentelle Medizin (WBex)
> >> Head of light microscopy
> >>
> >> Marchioninistr. 27
> >> D-81377 München
> >> Germany