"Flexture" refers to the type of mechanism that moves the sample stage relative to the objective lens. It means that instead of a high precision rack-and-pinion gear system that moves the stage, it uses "flexure joints" which don't necessarily need to be precision machined (they can be 3D printed).

In a flexture mechanism you apply force to a flexible bar and, because of geometry, that displacement gets translated and reduced into a much smaller displacement somewhere else. It only works with very small displacements (thus fine for microscopy). If you want to position the sample large distances, you just need to move the sample.

It's a neat idea made inexpensive by 3D printing, but the major expense here will be the optics (the objective lens). To get decent pictures of cells, like in a textbook, you're talking about $1K minimum, and it can go much higher, into the 10's, depending on application, performance and other optics (the light source and it's lenses).

Is it possible to use software to post process those images, apply a deconvolution filter and correct the optics?

Might that enable the use of cheaper lenses?

Unfortunately you can't recover information that was never captured, which is the main issue with cheaper lenses. They tend to have more abberations [1], which prevents capturing high quality information.

[1]: https://en.wikipedia.org/wiki/Optical_aberration

Do all optical aberrations go away if you use a curved image plane?

And if you correct aberrations in software then you can use the cheapest lenses (a single element objective and eyepiece) without having to correct for these aberrations in glass.

What if you shift the lens or sensor and capture multiple images, then process the result, would that be able to overcome chromatic abberation?

Well if you use narrowband colour filters (or light up the sample using narrowband LEDs) and refocus every time you switch, then you could eliminate chromatic aberration completely.

You would have to slightly rescale the image for each colour but that is not impossible.

Sounds like a tradeoff between processing time and image clarity / cost, same as computational photography in smartphones. That looks like a win to me, hopefully we will see innovations in this area so cheap microscopes with great resolving power becomes available to the masses.

Yes.

One problem in amateur astronomy is that people love spending money on expensive gear (like hifi audio nuts) and they think software is hard. So they sneer at technically complex solutions even if they end up cheaper in long run.

I assume microscopy has the same problem. Why make it cheap when you charge thousands of dollars for selling a top optical quality microscope?

I could be wrong. Haven’t tried it yet. But I haven’t given up on the idea yet.

No, a very good Chinese made RMS objective can cost less than $25 at lower magnification. Plan Achromatic objectives cost a little more, but will give flatter, clearer images than cheaper ones.

It seems a tube lens is used anyway, so the advantages of infinity system objectives are not as obvious. I’d stick to DIN160 or so called Olympus compatible objectives.

You'd be surprised at what you can accomplish with a couple hundred dollar plan achromat objective. (Though OpenFlexure's design complicates the use of immersion oil...)

Why are these kinds of lenses so expensive?

Thanks, that makes more sense!

"Optical" when talking about microscopes means it's using visible light rather than, say, electrons.

The main value of this is a low-cost precision positioning system that can be 3d-printed. A lot of the challenge of microscopy is getting the sample into the right place. And yes, this design can be motorised and controlled automatically as well.