Diatom from Nova Scotia, Silica Lake High power dark field

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MicroBob
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Diatom from Nova Scotia, Silica Lake High power dark field

#1 Post by MicroBob » Sun Apr 05, 2020 10:29 am

Hi together,
here two images of a diatom from Nova Scotia, Silica Lake with dark field contrast.
Zeiss West cardioid condenser, Zeiss West 100:1 with iris, second image Leitz NPL Fluotar 50:1 1,0.
32W LED at full power.

Bob
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Diatomee Dunkelfeld 100er Zeiss m.I. DSC_9773 1024.JPG
Diatomee Dunkelfeld 100er Zeiss m.I. DSC_9773 1024.JPG (168.2 KiB) Viewed 2086 times
Diatomee Dunkelfeld 50er Leitz NPL Fluotar 1,0. DSC_9848 1024.JPG
Diatomee Dunkelfeld 50er Leitz NPL Fluotar 1,0. DSC_9848 1024.JPG (177.07 KiB) Viewed 2086 times

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daruosha
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Re: Diatom from Nova Scotia, Silica Lake High power dark field

#2 Post by daruosha » Sun Apr 05, 2020 6:04 pm

Fascinating images Bob. Never seen diatom images like that. How do they look like under bright-field?
Daruosh.

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Seb28
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Re: Diatom from Nova Scotia, Silica Lake High power dark field

#3 Post by Seb28 » Sun Apr 05, 2020 6:17 pm

Nice.I like the second image most.
-Reichert Polyvar
-Olympus IX70
-Zeiss Photomicroscope
-Canon 600D

MicroBob
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Re: Diatom from Nova Scotia, Silica Lake High power dark field

#4 Post by MicroBob » Sun Apr 05, 2020 6:25 pm

I don't have a bright field image ready but here is a stacked epi dark field image of raw material of a similar species.
In bright field ist looks very special: Not so much a grid of pores but a shimmering surface with superficial dents. The shimmering look and the highly curved form make it difficult to obtain a good stacked image. The structure of this diatom is shown very well in the SEM images further down in this thread: https://www.mikroskopie-forum.de/index. ... ic=36290.0

The 100:1 was stopped down below n.a. 1,0 ang gave the darker backroung and better dark field look. But the full 1,0 aperture and the better correction of the Leitz 50:1 NPL Fluotar gave a better resolved image. I like both but they are quite different.

Bob
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Einzelne Diatomee 1024Bild 5.jpg
Einzelne Diatomee 1024Bild 5.jpg (160.16 KiB) Viewed 2062 times

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daruosha
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Re: Diatom from Nova Scotia, Silica Lake High power dark field

#5 Post by daruosha » Sun Apr 05, 2020 6:48 pm

Wow, once you understand the actual shape of this particular diatom, you realize the beauty of their image.

Thanks for sharing your pictures and more details.
Daruosh.

MicroBob
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Re: Diatom from Nova Scotia, Silica Lake High power dark field

#6 Post by MicroBob » Sun Apr 05, 2020 7:35 pm

And the character of the images is very different: My single shot is more a grim looking diatom, the SEM images have a detatched and neutral character. Stacking helps with sharpness but in some cases it gives a much too flattenend result, like in my epi darkfield image. In this case the SEM image is necessary to nuderstend the structure of the diatom - it has two layers and the pores just go through one of them.

Here an image focussed further down with the NPL Fluotar. This objective is mainly intended for uncovered blood smears and the objects have to be very close to the cover slip.
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Bearbeitet DSC_9858 1024.JPG
Bearbeitet DSC_9858 1024.JPG (107.55 KiB) Viewed 2052 times

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