Darkfield through glass edge illumination - Coleps
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Darkfield through glass edge illumination - Coleps
Experimenting using a single power LED illuminating the front edge of the glass slide.
Very pleased with the results. Some images look just like darkfield. The ones in this video were in murky waters, which make the images look absolutely 3 dimensional.
Not sure if this can really be called darkfield, but thought I'd share the results of such an easy illumination technique.
https://www.youtube.com/watch?v=_ScxA1wcDUc
Does anyone know what is that round blob that the 2 Coleps are trying to consume (bright field footage)?.
Thanks
Very pleased with the results. Some images look just like darkfield. The ones in this video were in murky waters, which make the images look absolutely 3 dimensional.
Not sure if this can really be called darkfield, but thought I'd share the results of such an easy illumination technique.
https://www.youtube.com/watch?v=_ScxA1wcDUc
Does anyone know what is that round blob that the 2 Coleps are trying to consume (bright field footage)?.
Thanks
Last edited by Chainsaw_DNA on Tue Mar 23, 2021 4:52 am, edited 1 time in total.
Re: Darkfield through glass edge illumination - Coleps
Very cool, I like the production I like to add music and effects to videos also
Re: Darkfield through glass edge illumination - Coleps
Very nice results! Can you show how you made the dark field lighting?
Re: Darkfield through glass edge illumination - Coleps
Hi, welcome.
I liked your Video, especially the cast shadow.
You might find this old post of interest
https://www.microbehunter.com/microscop ... o&start=30
I liked your Video, especially the cast shadow.
You might find this old post of interest
https://www.microbehunter.com/microscop ... o&start=30
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Re: Darkfield through glass edge illumination - Coleps
Congratulations! I use this method too. You can get a very nice effect by combining under-stage light with sidelight. It's particularly good at high power. I use two flashlights hitting the slide a slightly different sideways angles plus the under-stage light--carefully controlling intensity. The condenser increases depth of field. It's particularly good for bringing out small details like bacteria. You can buy a condenser on EBay or Amazon for a few dollars. When I had my first microscope, i bought one and glued it in place. What model do you have?
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Re: Darkfield through glass edge illumination - Coleps
Thanks, Sven! I'll work on a video with the details, but here are the simple basics:
The power supply should be able to easily adjust it's output voltage.
Caution to not exceed the maximum rating of the LED. For 5W LEDs, that is typically 0.7 Amps. I never go above 0.6 Ams. Preferably, get a power supply where you can set the maximum output current, like the one in the picture.
No heatskink is needed if you are not making the LED too bright. If you can't touch the LED's star heatsink, then it's too hot and you need the extra heatsink (highly recommended)
- 1 high power (5W) white LED.
- 1 DC power supply capable of easily varying the output voltage.
- 1 heat sink (highly recommended). This is in addition to the star heatsink that already comes with the LED.
The power supply should be able to easily adjust it's output voltage.
Caution to not exceed the maximum rating of the LED. For 5W LEDs, that is typically 0.7 Amps. I never go above 0.6 Ams. Preferably, get a power supply where you can set the maximum output current, like the one in the picture.
No heatskink is needed if you are not making the LED too bright. If you can't touch the LED's star heatsink, then it's too hot and you need the extra heatsink (highly recommended)
Re: Darkfield through glass edge illumination - Coleps
Liked your videos.
Have you tried this with something else beside pond critters? I'm wondering if the drop of water and coverslip act (along with the slide) as somewhat of a light pipe? If it also works with things like smears and dry mount slides, that could be doubly cool.
Have you tried this with something else beside pond critters? I'm wondering if the drop of water and coverslip act (along with the slide) as somewhat of a light pipe? If it also works with things like smears and dry mount slides, that could be doubly cool.
Re: Darkfield through glass edge illumination - Coleps
Thanks for the images! Very interresting. I would have expected that the light only should have iluminated the slide, like the link provided by hobbyst46. Cool.that this also works!
Re: Darkfield through glass edge illumination - Coleps
Fascinating. Got to give it a try. Wonderful video. Thanks for sharing!
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Re: Darkfield through glass edge illumination - Coleps
That's a piece of great work and ingenuity!
Greg
Greg
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Re: Darkfield through glass edge illumination - Coleps
Interesting! I'll have to try that!
I made some similar power LED setups for my my 380T but to use with the darkfield condenser:
Top one is a 10W LED on an aluminium bar, bottom a 3W just on a heatsink. Plus a variable psu though the LEDs are controlled by the constant current buck converters.
Louise
;
I made some similar power LED setups for my my 380T but to use with the darkfield condenser:
Top one is a 10W LED on an aluminium bar, bottom a 3W just on a heatsink. Plus a variable psu though the LEDs are controlled by the constant current buck converters.
Louise
;
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo
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Re: Darkfield through glass edge illumination - Coleps
I think it's probably an encysted ciliate/protozoan - unless someone else knows different?Chainsaw_DNA wrote: ↑Mon Mar 22, 2021 6:40 am
Does anyone know what is that round blob that the 2 Coleps are trying to consume (bright field footage)?.
Thanks
Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo
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Re: Darkfield through glass edge illumination - Coleps
Hi Hobbyst46. Thank you for the welcome and for the very interesting post on the work that you and others have done on edge illumination.Hobbyst46 wrote: ↑Mon Mar 22, 2021 7:22 amHi, welcome.
I liked your Video, especially the cast shadow.
You might find this old post of interest
https://www.microbehunter.com/microscop ... o&start=30
Have you heard of anyone experimenting with a laser beam that quickly sweeps the slide's edge?
Re: Darkfield through glass edge illumination - Coleps
Alas, no. Furthermore, I did not see many followers of Kawano's article about edge illumination. Perhaps MichaelG noticed progress in that direction.Chainsaw_DNA wrote: ↑Wed Mar 24, 2021 3:40 am...Have you heard of anyone experimenting with a laser beam that quickly sweeps the slide's edge?
The challenge in that type of illumination, I guess, is limitation of the light beam to the internals of the slide; total internal reflection, to create a true black background at high NA.
Re: Darkfield through glass edge illumination - Coleps
For those edge illumination darkfield, has any of you examined objective back focal plane to make sure objective aperture is sufficiently illuminated by peripheral circular light?
I apologize if I sound discouraging or harsh.
Some of the higher NA (0.65 and above) images presented here look as if objective aperture was not fully utilized.
A dedicated oil immersion darkfield condenser may be easily adapted to your microscope and provide even better darkfield images.
I am not seeing evidence than LED edge illumination would work better herein, unless edge illumination is evenly distributed and very carefully executed (which would be a more difficult task than simply adapting a real darkfield condenser, assuming your end goal is better images and not DIY fun). I did try LED edge illumination before, but in my hands it didn't work that well above NA 0.4 (20x objective); at NA 0.25 and 10x, it is very easy to get DIY dakrfield with a coin or a dark background + side lighting.
I apologize if I sound discouraging or harsh.
Some of the higher NA (0.65 and above) images presented here look as if objective aperture was not fully utilized.
A dedicated oil immersion darkfield condenser may be easily adapted to your microscope and provide even better darkfield images.
I am not seeing evidence than LED edge illumination would work better herein, unless edge illumination is evenly distributed and very carefully executed (which would be a more difficult task than simply adapting a real darkfield condenser, assuming your end goal is better images and not DIY fun). I did try LED edge illumination before, but in my hands it didn't work that well above NA 0.4 (20x objective); at NA 0.25 and 10x, it is very easy to get DIY dakrfield with a coin or a dark background + side lighting.
Re: Darkfield through glass edge illumination - Coleps
Saul, you bera version looks very promising, have you tested it on a mounted diatom, for example Pleurosigma or Gyrosigma species?
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Re: Darkfield through glass edge illumination - Coleps
Based on your tip, I've been reading about microbial cysts and that is the best classification that I've seen so far. Thanks, Louise!LouiseScot wrote: ↑Tue Mar 23, 2021 11:50 pmI think it's probably an encysted ciliate/protozoan - unless someone else knows different?Chainsaw_DNA wrote: ↑Mon Mar 22, 2021 6:40 am
Does anyone know what is that round blob that the 2 Coleps are trying to consume (bright field footage)?.
Thanks
Louise
Re: Darkfield through glass edge illumination - Coleps
This is a cool concept-definitely deserves experimentation-this is probably a stupid idea but I’ve always wondered with this technique about painting the entire slide with white nail polish or whatever including the sides except the side being illuminated and just leave enough unpainted space in the middle for a coverslip so any side illumination is bouncing back from all painted surfaces-is this a silly idea? I never know with my brain style!
Regards
Regards
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Re: Darkfield through glass edge illumination - Coleps
Not a stupid idea at all!Rossf wrote: ↑Mon Mar 29, 2021 12:33 amThis is a cool concept-definitely deserves experimentation-this is probably a stupid idea but I’ve always wondered with this technique about painting the entire slide with white nail polish or whatever including the sides except the side being illuminated and just leave enough unpainted space in the middle for a coverslip so any side illumination is bouncing back from all painted surfaces-is this a silly idea? I never know with my brain style!
Regards
Here is a picture of what I use, which clearly improves the image quality. This white, 3D printed shroud bounces the escaping light, back into the slide edges. This is essentially what you mentioned, but using plastic instead of nail polish.
The opening at the middle-bottom is where the single, high power LED shines the light into the slide's edge.
This technique allows me to see "darkfield" using the SW380T with it's original 40x objective and an aftermarket 60x objective.
Here is another picture, showing the original version of the first picture and a version with a cutout where the coverslip goes, which gives darker backgrounds.
Re: Darkfield through glass edge illumination - Coleps
Yay! Not as dumb as I thought I was! Cheers Chainsaw_DNA! I even thought about the bottom gap of paint where the coverslip goes but didn’t mention it-have you tried covering the top of the slide with plastic as well?-might be overkill but I’m all for throwing in every idea when I’m in an experimental mood..-by the way I really like that murky 3-D look a lot! Maybe cos I use mainly inverted so pretty used to not as sharp but more 3-D looking images with low N/A’s most inverted objectives have-I have a 25x with N/A .22(!) and it images fungal hyphae beautifully-but is pretty useless at anything else..but still a keeper.
Regards ross
Regards ross
Re: Darkfield through glass edge illumination - Coleps
I just realised I missed the most obvious advantage of this technique-having DF with a 40x and 60x without needing an iris is pretty damn cool!
That it. I’m just gonna have to experiment with this technique.
R
That it. I’m just gonna have to experiment with this technique.
R
Re: Darkfield through glass edge illumination - Coleps
This indeed was some of the motivation of the researcher (Kawano) who several years ago published his version of the whole slide illuminator.
BTW, the white pain or plastic wrap shown above do not contribute significant total reflection within the slide, in my opinion. They can prevent stray light, that is light that hits the specimen on the slide from above or from below, for example when the illuminator beam is thicker then the slide or hits the slide not exactly horizontally. I think black paint might be somewhat better. But anyway, the external coating does not return escaping light back into the slide. There are coatings that would do that (certain teflons).
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Re: Darkfield through glass edge illumination - Coleps
Being able to use higher magnification was my primary motivation.
While the SW380T works well with the 4X and 10X objectives, I have not had any luck making darkfield with the 40X objective, and above.
Be aware that the success of edge illumination is highly dependent on the specimen. I've had some success with amoebas and diatoms, but nothing great. Coleps are the best specimen that I've seen so far.
With edge illumination, I get videos that would be impossible otherwise, unless someone can show me how to properly setup my microscope for darkfield using 400X total magnification, and above.
[youtube]https://youtu.be/Xw5ztJMZP1o[/youtube]
I've seen improvement using the white plastic shroud, using a dry slide with diatoms. I'll need to experiment with specimens in water and post a comparison video.
While the SW380T works well with the 4X and 10X objectives, I have not had any luck making darkfield with the 40X objective, and above.
Be aware that the success of edge illumination is highly dependent on the specimen. I've had some success with amoebas and diatoms, but nothing great. Coleps are the best specimen that I've seen so far.
With edge illumination, I get videos that would be impossible otherwise, unless someone can show me how to properly setup my microscope for darkfield using 400X total magnification, and above.
[youtube]https://youtu.be/Xw5ztJMZP1o[/youtube]
I've seen improvement using the white plastic shroud, using a dry slide with diatoms. I'll need to experiment with specimens in water and post a comparison video.
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Re: Darkfield through glass edge illumination - Coleps
Thanks, PeteM. I only tried with slides that had dried out and left behind Diatoms and substrate. In those cases, there was some success. But that was the limit of my experience with dry slides.PeteM wrote: ↑Tue Mar 23, 2021 4:56 amLiked your videos.
Have you tried this with something else beside pond critters? I'm wondering if the drop of water and coverslip act (along with the slide) as somewhat of a light pipe? If it also works with things like smears and dry mount slides, that could be doubly cool.
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Re: Darkfield through glass edge illumination - Coleps
LouiseScot wrote: ↑Tue Mar 23, 2021 4:44 pmInteresting! I'll have to try that!
I made some similar power LED setups for my my 380T but to use with the darkfield condenser:
10W and 3W LEDs.jpg
Top one is a 10W LED on an aluminium bar, bottom a 3W just on a heatsink. Plus a variable psu though the LEDs are controlled by the constant current buck converters.
Louise
Hi Louise. Which darkfield condenser did you use, and did you get acceptable results?
I've been trying to get DF to work with the stock SW380T condenser but I've only had good results at lower magnifications. I have not been able to get DF with 40X and 60X objectives.
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Re: Darkfield through glass edge illumination - Coleps
HiChainsaw_DNA wrote: ↑Fri Apr 02, 2021 6:50 amLouiseScot wrote: ↑Tue Mar 23, 2021 4:44 pmInteresting! I'll have to try that!
I made some similar power LED setups for my my 380T but to use with the darkfield condenser:
10W and 3W LEDs.jpg
Top one is a 10W LED on an aluminium bar, bottom a 3W just on a heatsink. Plus a variable psu though the LEDs are controlled by the constant current buck converters.
Louise
Hi Louise. Which darkfield condenser did you use, and did you get acceptable results?
I've been trying to get DF to work with the stock SW380T condenser but I've only had good results at lower magnifications. I have not been able to get DF with 40X and 60X objectives.
I modified the Swift to take an Amscope dry darkfield condenser - I 3D printed a simple condenser holder and just used the existing screw holes on the stage. I posted about it on the forum
Louise
A Nikon CF plan 20x; A Swift 380T; A DIY infinity corrected focus rail system with a 40x/0.65 Olympus Plan, a 10x/0.30 Amscope Plan Fluor, and a 20x/0.75 Nikon Plan Apo