http://confocal-microscopy-list.275.s1.nabble.com/Numerical-aperture-and-spatial-resolution-tp7591293p7591330.html
> why capturing more diffraction orders means higher resolution.
well, in my understanding it does not. As far as I get it, it is only
about the first diffraction order that you need to collect. But you
1. Higher NA means larger acceptance angle. (Trivial to microscopists,
but worth mentioning with the students). This also helps with intensity
2. the smaller an object/structure is, the larger the angle of its
diffraction pattern will be. (WHY this is the case, that is the
difficult bit. But in my experience biology students are happy to just
various stripe patterns can be used. Just shine a laser through it and
look at the different diffraction patterns on the wall behind. That you
can do in a video class. Even better is to produce a small white dot
patterns in front of their eye. Then you also see the differences for
the wavelengths. But this won't work online. Maybe it someone did a
stripe pattern slide idea again goes back to Peter Evennett. We have a
> *****
> 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,
>
> Thanks to all contributors for the excellent suggestions.
>
> Unfortunately, at the present times, at least here in Madrid, most if
> not all university lectures are Teams sessions. So on-site demos are
> not a choice.
>
> I also align with Zdenee's view. "Why does higher NA mean higher
> resolution?" is a question with no trivial answer for biologists. The
> demo of looking the diffraction orders at the BFP with a Bertrand
> lens, using objectives with different NA and gratings of different
> densities, worked best for me when I first learned about spatial
> resolution. Still, for a biology undergraduate is difficult to
> comprehend intuitively why capturing more diffraction orders means
> higher resolution.
>
> Javier
>
>
> El 19/09/2020 a las 20:27, Zdenek Svindrych escribió:
>> *****
>> 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 George and Javier,
>>
>> regarding aperture and resolution of DSLR (actually mirror-less) I
>> put some
>> photos together here:
>>
https://drive.google.com/file/d/1vDYqDBPgapZYad3JahRm8R5W5Bkwu4T6>> But, it will only work with some lenses (well, with most, but not in the
>> full F-stop range), and only with some cameras (more pixels is better
>> here,
>> kind of an exception :-).
>>
>> Davide, the Evenett's video is great! Many demonstrations were quite
>> surprising, and I have nothing to add to it (maybe a note, that the
>> phase
>> contrast method in all its simplicity still yielded Zernike a Nobel
>> prize!).
>> But even though one thought follows from another nicely, at the end
>> if you
>> ask your students "So why does higher NA mean higher resolution?"
>> they'll
>> say "Well, uhm..." It's not very likely they'll gain a deeper
>> understanding
>> of how all these concepts fit together.
>>
>> Good luck!
>>
>> zdenee
>>
>> On Sat, Sep 19, 2020 at 12:25 PM George McNamara
>> <
[hidden email]>
>> 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 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:
>>>> *****
>>>> 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.
>>>> *****
>>>>
>>>> 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
>>>>
>>>>
>>
Steffen Dietzel, PD Dr. rer. nat