MicrobeHunter.com Microscopy Forum

I have recently taken an interest in adapting Charles Krebs' Photomicrographic setup. However, I am concerned with the risk of disassembling the flash unit that he used and any potential damage to my Olympus BHS's lamphousing. An alternative I have thought of is using s a Y fiber optic cable connected to a flash unit and my light source. With this in mind, can the light emitted by the fiber optic cable completely fill the illumination field of any microscope with a collector lens at its back?

The polished end of a fibre optic cable will emit light at a certain angle which [varies a with the refractive index of the fibre but] will look something like this:
. .

MichaelG.
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Note:__ My photo is of a 1mm bundle illuminated by a green laser, but the geometry is scaleable.

Thank you for the reply @MichaelG. One thing of note is that are there fiber optic cables that take two inputs but only release one? Eg. I can link a fiber optic cable to my background light and a flash unit to one cable?

I’ve just searched my ‘bookmarks’ and found these … which might be of interest:

https://www.micromagus.net/microscopes/flashsetup.html

https://www.micrographia.com/articlz/ar ... pc0100.htm

MichaelG.

MicroMan2 wrote: ↑

Wed Nov 16, 2022 6:12 am

Thank you for the reply @MichaelG. One thing of note is that are there fiber optic cables that take two inputs but only release one? Eg. I can link a fiber optic cable to my background light and a flash unit to one cable?

.

… Yes, but they are normally sold as splitters [and are typically ‘not inexpensive’]
… you just need to use them in reverse.

https://www.astroshop.eu/light-conducto ... mm/p,48493

MichaelG.

Splitters can be readily found inexpensively on the used market. I would suspect you'd need to be sure it had jumbled fibers rather than orderly ones so they produce the same approximate shape and location of light.

If you are interested in a different approach, this link has a large number of ways to set up a flash for photomicroscopy.

https://www.photomacrography.net/forum/ ... hp?t=26185

Bumping this thread as I think I am changing my approach. I've recently perused a variety of Flash Photomicrography setups and recently saw David Walker's setup with a beamsplitter linked here: http://www.microscopy-uk.org.uk/mag/ind ... lash2.html .Wanting to replicate this setup given its relative ease compared to my initial fiber-optic idea, I wanted to find a source of optical beamsplitters. I have checked Ebay and I am skeptical of their quality and I am not sure if stores like Edmund Optics sells to individuals. Does anybody know any supplier of optical beamsplitters of good quality that sells to individuals?

It’s always worth having a look at SurplusShed

Fred has an enormous stock, and some real bargains

MichaelG.
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https://www.surplusshed.com/

and recently saw David Walker's setup with a beamsplitter

Looking at that splitter I am wondering whether the silvered plastic film that people used to stick on windows might work ..I have some here and it doubles or slightly more the exposure to transmitted light.
It is less reflective that the standard plastic mirror film, but it also blocks much less of the transmitted light.
I guess it depends on whether you can think of someone who might have a bit, to try out.

If it is of any value in thinking around the amount of light; with a 40x objective and a Guide Number 58 flash gun set to 1/128 power pointing directly into the condenser. It didn't need the condenser's iris over-closing too much to get a photo, at ISO100: (There was a lens tissue over the flash-head to get rid of the rainbows from the fresnel lens.)

So perhaps a simple 90 degree (100%) mirror box attached to a flashguns head might be a starting point?
To get an idea of the view before taking a pic the tissue was lit with a small LED desk light.

A removable/swing out ND filter under the condenser might make it a better setup.

EDIT: The Guide Number of number of the modern flashgun I used isnt really comparable to, say, the GN of a Vivitar 283 as it has zooming optics in its head, so whilst it can illuminate a long distance and so would appear to have a high GN, this isnt really a measure of its basic output (unlike the 283's Guide Number).

Chas wrote: ↑

Mon Nov 28, 2022 7:47 pm

and recently saw David Walker's setup with a beamsplitter

Looking at that splitter I am wondering whether the silvered plastic film that people used to stick on windows might work ..I have some here and it doubles or slightly more the exposure to transmitted light.
It is less reflective that the standard plastic mirror film, but it also blocks much less of the transmitted light.
I guess it depends on whether you can think of someone who might have a bit, to try out.

Have you considered using a simple glass plate beamsplitter ?
… probably quite adequate as it’s not in the image-forming path.

https://www.edmundoptics.eu/knowledge-c ... splitters/

MichaelG.

Have you considered using a simple glass plate beamsplitter ?

There is a nice list of links to various flash setups, some of which use complete flashguns (less risk), some with glass plate beamsplitters, here:

https://www.photomacrography.net/forum/ ... hp?t=26185