Rotating Stage DIC Demonstration

[KurtM]

Back in July (2020) I submitted a thread showing how I grafted a Zeiss rotating stage onto my Olympus BH-2, see: viewtopic.php?f=24&t=9924&p=84494#p84494

A discussion followed as to why a rotating stage is wanted. The short answer is that a lot depends on how the specimen is presented to the DIC shear plane, and while not quite the same thing, it's still similar to how oblique illumination is affected by the direction the light is coming from. Ever since that thread I have wished I had given a visual example of how this works, and so now is as good a time as any to make up for the deficit.

The following three images show a diatom specimen where nothing is adjusted between shots except rotation; all other camera and microscope settings remain untouched; the sole differences between frames being that the stage is rotated in 45 degree increments, and the camera follows in rotation to maintain frame orientation. The images are straight out of the camera, no tweaks other than resizing.

[MicroBob]

Hi Kurt,
thank you for this interesting comparison!
My main microscope is a Zeiss Phomi 1. I normaly use it with a rectangular stage with low controls, ideal for quick moving subjects. But I also have the original rotating stage but no extra holder for it. The original tube head is so that the objectives swing back and the x-axis of the stage is towards the operator, which makes handling difficult. But I have a newer tube head for some time now and could use the stage the other way round, as the nosepieces can be inserted in two orientations. I think I have to give this a try!

Bob

[KurtM]

Hey Bob, you bring up an excellent counter point, and that's that the rotating capability isn't beneficial to all subjects. Besides something like live protists, it's useless for centric (round, circular) diatom forms! In the meantime, the X-Y stage controls are ever so much more ergonomic on nonrotating stages with the coaxial drop wand knobs. Can't have those on rotating stages ... "there is no free lunch".

[Hobbyst46]

Hey Bob, you bring up an excellent counter point, and that's that the rotating capability isn't beneficial to all subjects. Besides something like live protists, it's useless for centric (round, circular) diatom forms! In the meantime, the X-Y stage controls are ever so much more ergonomic on nonrotating stages with the coaxial drop wand knobs. Can't have those on rotating stages ... "there is no free lunch".

Kurt, there was an Olympus rotating microscope X_Y stage with coaxial drop wand knobs, although it was not full rotation I think...(pre-BH era).

[viktor j nilsson]

Very nice demonstration! I love having a rotating stage, wouldn't want to be without it.

Olympus made square rotating stages with low drive controls both during the BH/Vanox AH era, and during the BH-2/Vanox AH2 era.

Here's a screenshot from the BH-2 manual on Alan Wood's site: