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Description

Five different illumination techniques for the same microscopic subjects: a couple of diatoms .

Bright-field : the most common and the first in history.
Bright-field with oblique illumination , obtained with a de-centerable condenser.
Dark-field : obtained with dedicated condenser, standard white light.
Rheinberg illumination: a variant of dark-field illumination; same condenser than before, but with a red ring and a blue center filter.
Phase-contrast : here I’m using a variable phase-contrast (phv) condenser and objective, first setting.
Same than before, but with the second setting, more similar to modern common single level phase-contrast.
I used a very old Carl Zeiss Jena equipment:

Ergaval stand
Apochromat 16/0.40 160/0.17 objective for images 1-4
Planachromat 16/0.32 160/0.17 Phv objective for images 5-6
MF-Projectiv 4:1 projection eyepiece
De-centerable condenser Aplanatic N.A. 1.4 for images 1-2
Dark-field condenser N.A. 0.65 (?) for images 3-4
Phv Aplanatic N.A. 0.9/e condenser for images 5-6
LED illumination
Sony NEX-6 camera (sorry for the bands produced)
The slide was made by Stefano Barone, Diatom Lab, a strew from an Oamaru sample.

Post-processing: clipping (a lot), white-balance adjustment, levels adjustment, a bit of sharpening, noise reduction and chromatic aberrations corrections.

Description

Five different illumination techniques for the same microscopic subjects: a couple of diatoms .

Bright-field : the most common and the first in history.
Bright-field with oblique illumination , obtained with a de-centerable condenser.
Dark-field : obtained with dedicated condenser, standard white light.
Rheinberg illumination: a variant of dark-field illumination; same condenser than before, but with a red ring and a blue center filter.
Phase-contrast : here I’m using a variable phase-contrast (phv) condenser and objective, first setting.
Same than before, but with the second setting, more similar to modern common single level phase-contrast.
I used a very old Carl Zeiss Jena equipment:

Ergaval stand
Apochromat 16/0.40 160/0.17 objective for images 1-4
Planachromat 16/0.32 160/0.17 Phv objective for images 5-6
MF-Projectiv 4:1 projection eyepiece
De-centerable condenser Aplanatic N.A. 1.4 for images 1-2
Dark-field condenser N.A. 0.65 (?) for images 3-4
Phv Aplanatic N.A. 0.9/e condenser for images 5-6
LED illumination
Sony NEX-6 camera (sorry for the bands produced)
The slide was made by Stefano Barone, Diatom Lab, a strew from an Oamaru sample.

Post-processing: clipping (a lot), white-balance adjustment, levels adjustment, a bit of sharpening, noise reduction and chromatic aberrations corrections.