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- I finally obtained a set of epi-phase microscope objectives (Zeiss)
Well, it took almost 20 years (!!!), but I finally obtained a set of epi-phase microscope objectives (Zeiss). The principles of epi-phase contrast is nearly identical to transillumination phase contrast, but the phase ring is a 1/8 wave retarder rather than a 1/4 wave retarder (because with epi-illumination, the light passes through the ring twice). This method was popular only for a very short period of time before epi-DIC (differential interference contrast) became widely available. So, not only are epi-Ph lenses impossible to find, but they are cheap because nobody wants them :)
Here are 4 images of a razorblade comparing the different epi illumination methods, all using 40x lenses. In order: brightfield, phase contrast, DIC, and darkfield:
While epi-phase looks a bit like epi-darkfield, the biggest difference is the light throughput- 1/30 s shutter (phase) instead of 5 s (darkfield).
Success! I feel like Captain Ahab, if he had finally caught Moby Dick. But I guess that would moot the point of the story....
Here are 4 images of a razorblade comparing the different epi illumination methods, all using 40x lenses. In order: brightfield, phase contrast, DIC, and darkfield:
While epi-phase looks a bit like epi-darkfield, the biggest difference is the light throughput- 1/30 s shutter (phase) instead of 5 s (darkfield).
Success! I feel like Captain Ahab, if he had finally caught Moby Dick. But I guess that would moot the point of the story....
