BIOLOGY 207 Lecture Notes - Lecture 3: Javanese People, Microtome, Electron Microscope
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And so let"s quickly walk through these dark eld ops optics, so below the condenser is this spider light stop that excludes all but an annular ring of light so this is sort of like an empty cone. So you have this cone of light, with no light inside it, and then you have this condenser, that allows for the focal plane to reach the specimen. So why is dark eld so useful. Well, one thing that you can do is resolved structures that are below the resolution of bright eld microscopy below 200 nanometers so for example agella are way to narrow to be detected via bright eld. He"s agell are the little whip like protrusions from bacteria that allow them to swim. So you always see the cell bodies you don"t see any agella here, but look what happens when you increase the intensity of life.
