Posted by
George McNamara on
URL: http://confocal-microscopy-list.275.s1.nabble.com/Numerical-aperture-and-spatial-resolution-tp7591293p7591298.html
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Hi Javier,
I suggest you ask the class if they have any interest in taking photos
with their smartphone or DSLR camera, and if they do, bring in a DSLR
and tripod and computer/projector (if the room does not have that
already), explain f/stop and NA are inverse of each other, and
demonstrate NA (resolution, intensity, depth of field) on the class by
focusing on faces in the middle row. Wavelength: yes, you could buy some
filters for the camera lens (or deal with separating channels in
Photoshop, fiji ImageJ, etc), but probably better done on a microscope.
George
p.s. this post was inspired by a conversation yesterday -- Friday happy
hour -- with a colleague, Prof. Jim Potter, who told me about a
conversation he had with someone with a very expensive digital camera
hobby, who only used their cameras set to auto. Jim explained f/stop,
ISO and more (framing scene etc). My thanks to Jim for good story with
nice timing and especially foraging for the beverages.
A fun (in theory, but probably not practical or wise) wavelength test
would be to use bring in blue (~400 nm) and NIR (~800nm would be nice,
values chosen to be 2 fold, not necessarily practical) and a smoke
machine (and some 400nm and NIR friendly lighting in case room lights
too dim at those wavelength), and demonstration resolution vs ability to
see through the smoke (Mie scattering etc). If you do this, and the
smoke alarm turns on, your school may not be happy with you (though all
the students may be happy to escape class early).
Of course if they vote no to learning about f/stop and NA, you can ask
them how they expect to get to a million TikTok followers each without
knowing how to take good quality videos. Come ot think of it, if they do
vote yes, and you put your demo on your TikTok feed and make a lot of
money, you can send me the URL and a thank you check.
On 9/19/2020 5:38 AM, F Javier Diez Guerra wrote:
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>
http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy> Post images on
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>
> Hello,
>
> I wonder if anybody in the list could help.
>
> I want to convey to biology undergraduate students (very allergic to
> physics and mathematics) the understanding of the relationship between
> numerical aperture and spatial resolution.
>
> I have already given them links to the different microscopy primer
> sites. They find difficult to understand why the airy disk is
> generated in the image plane, how the diffraction orders affect
> resolution and why increasing NA reduces the image spot.
>
> Could anybody share a basic and intuitive infographic slide, animation
> or any other resource that could help to ease comprehension in this
> context?
>
> Thanks
>
> Javier
>
>