Sigma's Foveon sensors have long had a small but loyal following who love their sharp images and vibrant, accurate colors. Since the advent of the L mount alliance, there has long been the hope that the Foveon sensor might find its way into a full frame camera. Sigma's CEO recently confirmed that those hopes might soon come true.
In a recent interview, Sigma CEO Kazuto Yamaki discussed the company's progress on developing a full frame Foveon sensor, noting that it has been difficult to enlarge the sensor to full frame size. That being said, the company feels encouraged by their current progress and hopes to aim for a 2024 release.
Foveon sensors are fundamentally different from the more common Bayer filter sensor. In a Bayer sensor, each pixel is exposed only to red, blue, or green light (due to the presence of a filter). This means that the final image must undergo demosaicing, a process by which a pixel's full RGB value is assigned based on its value and the values of nearby pixels. On the other hand, a Foveon sensor takes advantage of the varying penetrative abilities of different wavelengths, allowing each pixel to have a full RGB measurement.
Because of their fundamentally different structure, Foveon sensors also have far different behavior. Color artifacts are greatly reduced, and anti-aliasing filters are often not as necessary. Foveon sensors often produce particularly detailed images with impressive color. On the other hand, they generally perform worse at higher ISOs and thus are meant to be used in good light. Certainly, a high-resolution full frame Foveon sensor in tandem with modern high-level optics would be quite interesting for applications like landscape and studio photography. Hopefully, we'll hear more soon.
Foveon has always been a good idea, but even after surviving 24 years, I don't see it going too far in its current marketing situation. For me high ISO issues are not a problem in product photography and I could certainly see how a full frame Foveon could be great for what I do. Buying a Sigma camera, let's be real, not going to happen. Put it in a Fuji and I will feel much more comfortable. I don't think it's the technology that's the problem.