The short E-mount flange distance has one “drawback”. Lenses have to be larger to correct the incident angle at the corner which usually causes heavy color shifting, huge vignetting and loss of sharpness. That’s why Voigtlander redesigned the Heliar 15mm III lens (here on eBay). And the new design makes the new lenses twice as big as the predecessor.
Sony seems to have acknowledged that there is an issue to be solved. Egami spotted a new Sony sensor which packs a couple of innovations. First of all this is a multilayered sensor (and not a classic RGB Bayer). And the second innovation is that there is a lens on the sensor that corrects the angle of the light hitting the sensor. With that solution the light hits the full sensor with the right angle. It would allow lenses to be more compact because they don’t have to uses more glass to correct the angle.
On paper it would also allow all third-party lenses (particularly wide-angle lenses) to work flawlessly on Sony FE cameras. Let’s hope the next generation FE camera will come with such a sensor. Exciting!