Actually, fluid lenses aren't so new, the "unusual Panoramic Lens of T.
Sutton (1859), fig 83, containing water is an extreme example of a
symmetrical system, but it was not used much as the image was formed on
a spherical surface" -- the late, esteemed, R. Kingslake from 'Lenses in
Photography' (1951).

I've been watching the online news releases on these lenses.  Perhaps the
lens design gurus that frequent here could respond.

One point that is made is that the diameter of the lenses are currently
limited as the chances of the oil and water mixing goes up as the diameter
goes up. I guess we won't be seeing a 180mm f5.6 lens for large format any
time soon. As diameters increase I wonder if the surface will "sag" as
gravity takes a larger role in the shape of the oil/water surface.

They talk about the lens being a sphere. So much for aspherical lenses...

My understanding of coatings leads me to wonder if the water-oil surface
will see a need for "coatings"  Such lenses are going to have two
air/glass-or plastic surfaces, an oil/glass-of-plastic surface, a water/oil
surface, a water/glass-or-plastic surface. Are internal reflections and
therefore contrast an issue?  Or course one advantage is that with the
exception of the oil-water surface, coatings can be introduced and each of
those boundaries could probably be shaped to add come corrections to the
optical quality of the single surface spherical "lens"

Don't get me wrong, I think that the technology it great.  Has potential in
all sorts of applications.  I'm just doubtful of this technology replacing
mechanics and glass in fine art and in journalistic photography in the near
future.  Medical, surveillance, "photo phones", Dick Tracy wristband
teleconferencing phones, sure.

Todd