Sigma working on a full-frame Foveon sensor

It seems that Sigma's ready to join the full-frame mirrorless party, but it's bringing its own twist: a Foveon sensor. 

The company's president confirmed its plans, as well as the decision to drop its proprietary SA mount, in an interview at Photokina 2018. (Here's Photolari's report.) The moves are somewhat unsurprising since Sigma just joined Panasonic and Leica in the L-mount Alliance. Panasonic's using its own sensor for its debut full-frame models, the S1R and S1.

Don't remember the Foveon sensor? It uses a stacked RGB filter array rather than the scattered RGB filters you typically find in cameras. Despite its promise of better color, it never caught on. That was partly because the cameras using it were such oddballs, but also because Sigma defined "resolution" differently than the rest of the market, making it a harder sell.