Darkfield on a stereo scope

Here you can discuss different microscopic techniques and illumination methods, such as Brightfield, Darkfield, Phase Contrast, DIC, Oblique illumination, etc.
Post Reply
Message
Author
User avatar
Radazz
Posts: 982
Joined: Sat Jun 18, 2016 11:55 am
Location: Arnold, Missouri USA

Darkfield on a stereo scope

#1 Post by Radazz » Mon Dec 10, 2018 4:21 am

This was easier than I thought.
You need a black background, and to avoid seeing the image of whatever is used for the background, I placed the subject, a male Culex mosquito, on a thick piece of glass to throw the black surface out of focus.
Image

Next, I dropped the ring light around the specimen.
Image

Not bad, and so easy I stumbled upon it.
Image

Enjoy,
Radazz
Arnold, Missouri
Olympus IX70
Olympus BX40
Olympus SZ40

User avatar
mrsonchus
Posts: 3788
Joined: Tue Feb 03, 2015 9:42 pm
Location: Cumbria, UK

Re: Darkfield on a stereo scope

#2 Post by mrsonchus » Mon Dec 10, 2018 1:24 pm

Ha!Good work Radazz!

I made black-card discs to get the darkfield effect with my stereo 'scope,
the disc is the same size as the bottom of the container.
DF stereo disc (1).jpg
DF stereo disc (1).jpg (17.25 KiB) Viewed 2151 times
With container,
DF stereo disc (2).jpg
DF stereo disc (2).jpg (19.79 KiB) Viewed 2151 times
As you say, the height of the specimen is alterable and changes how much light reaches it....

John B.
John B

User avatar
Radazz
Posts: 982
Joined: Sat Jun 18, 2016 11:55 am
Location: Arnold, Missouri USA

Re: Darkfield on a stereo scope

#3 Post by Radazz » Mon Dec 10, 2018 2:21 pm

Cool solution, my friend!
Yours might have less glare.
I’m waiting for a translucent stage insert for the base, which will let me try your solution.
Thanks,
Jim
Arnold, Missouri
Olympus IX70
Olympus BX40
Olympus SZ40

User avatar
mrsonchus
Posts: 3788
Joined: Tue Feb 03, 2015 9:42 pm
Location: Cumbria, UK

Re: Darkfield on a stereo scope

#4 Post by mrsonchus » Mon Dec 10, 2018 2:29 pm

Hi Jim, let us know how it goes, it's an interesting area for a stereo 'scope, especially with the translucency of my mossy friends.

John B.
John B

crb5
Posts: 5
Joined: Sat Sep 12, 2020 11:55 pm

Re: Darkfield on a stereo scope

#5 Post by crb5 » Tue Sep 15, 2020 5:46 pm

Just discovered this thread. I made a darkfield condenser for a stereo microscope using an ice cream jar lid, a soft drinks can as a reflector and black electrical tape as a back stop.

https://www.youtube.com/watch?v=TIXAr5cCDOc

Might need a bit a trial and error to get the optimal dimensions but it costs zero.

Element 56
Posts: 241
Joined: Thu Oct 13, 2016 3:48 pm
Location: Lancaster County, PA

Re: Darkfield on a stereo scope

#6 Post by Element 56 » Tue Sep 15, 2020 9:19 pm

Very interesting and simple! Thanks for sharing it.

Ever try to make a shadowless illuminator? This was in the most recent Quekett Bulletin. I really want to try it but haven't gotten a round to it.
IMG_15092020_171605_(600_x_800_pixel).jpg
IMG_15092020_171605_(600_x_800_pixel).jpg (115.48 KiB) Viewed 121 times
Kirby

Post Reply