Yeah. It currently works in infrared (though they say it can be modified to visible light) and the video from the lab shows the images to look quite noisy and blurry, honestly.
Depending on the wavelength of the infrared even noisy and blurry may be notable or it may be mediocre for their setup. All the important details are in the paywalled paper so which type of infrared they calibrated for is unknown.
Just too much stuff missing from the article to actually judge for technical merit.
And plus making one for visible light is likely the main challenge as micro machining precision optics is not subject to moore’s law type scaling. Though I wouldn’t put it past Apple to sink billions into it if it helps making camera modules a few mm thinner.
At the claimed 180 degree field of view? Yes. Fisheyes that wide have lenses that are not only incredibly thick, but also bulbous enough that protecting the lens is quite difficult.
For an add-on lens yes. It’s probable Apple already has prototype lenses optimized for thinness that are less than a cm thick, since a lot of the bulk is unnecessary if it’s directly integrated to the sensor.
