“Is there not a thing you can hook to your DSL and your microscope? To shoot through the eye piece. I bet that is how it is done! At 30x prob.”
There are step-down adapters to connect a dSLR body to the eyepiece tube of a microscope. You’re ending up with a much narrower field of view hitting the sensor, but with the D810 that might be a satisfactory resolution. However, since you’re not focusing a camera lens, tethering cannot control the focus increments. You’re doing that manually on most scopes, and the accuracy of the steps depends a lot on the quality of the scope’s fine-focus. Focus-stacking manually is tedious; fortunately my tethering software handles that well now.
Here’s the field of view you get with a 10X microscope lens and a digital imager. This was shot with a 2 megapixel Celestron imager dropped into the eyepiece tube. Back when I got this, I thought it was a lot of detail. My dSLR captures better detail with far less noise now. 🙂 This image was focus-stacked from 47 still images–like I said, tedious to do! I generated a 3D simulation from the depth map. It’s interesting to look at, but I can’t say I see anything more than my dSLR shots.