Sigma has published a status update regarding the development of one of its most complex and challengeable projects, which is a full-frame camera that is based on the Foveon X3 sensor. Read Sigma CEO statement below. 

Foveon X3 sensor: The digital mimication of film

The operation of the Foveon X3 sensor is different from that of the Bayer filter image sensor, which is more commonly used in digital cameras. In the Bayer sensor, each photo-site in the array consists of a single light sensor (either CMOS or CCD) that, as a result of filtration, is exposed to only one of the three primary colors: red, green, or blue. Constructing a full-color image from a Bayer sensor requires demosaicing, an interpolative process in which the output pixel associated with each photo-site is assigned an RGB value based in part on the level of red, green, and blue reported by those photosites adjacent to it. However, the Foveon X3 sensor creates its RGB color output for each photo-site by combining the outputs of each of the stacked photodiodes at each of its photosites. The concept for this design was born as a mimication to film cameras. Explore the scheme below: 

Foveon X3 advantages (and disadvantages):

Because demosaicing is not required for the Foveon X3 sensor to produce a full-color image, the color artifacts associated with the process are not seen (“X3” stands for the three-layer structure used in Sigma’s Foveon sensors. Foveon X3 Direct Image sensors use three layers of pixels embedded in silicon to capture the color that other image sensors miss). On the other hand, the method of color separation by silicon penetration depth gives more cross-contamination between color layers, meaning more issues with color accuracy. The Foveon X3 photosensor can detect more photons entering the camera than a mosaic sensor because each of the color filters overlaying each photosite of a mosaic sensor passes only one of the primary colors and absorbs the other two. However, the absorption of these colors reduces the total amount of light gathered by the sensor and destroys much of the information about the color of the light impinging on each sensor element. However, there’re unsolved issues regarding file opening and post-production compatibilities.

For those who are brave enough to dive into the details, check out the article below that explains the development challenges of the Foveon X3 image sensors technologies: 

[pdf-embedder url=”https://ymcinema.com/wp-content/uploads/2021/02/Foveon-Sigma.pdf” title=”Development Challenges of a New Image Capture Technology: Foveon X3 Image Sensors”]

Sigma updates the status of development

Here’s the Sigma CEO statement that explains the mass production challenges and muddles. Briefly, the camera body has not been designed yet. And it seems that the team is getting back to the drawing table:  “In February 2020, we announced our decision to restart our plans for a full-frame Foveon X3 sensor camera, beginning with the development of new sensor technology. We have not been able to share any information regarding this project in the time since, and I would like to use this short message to provide an update about the situation. As previously announced, we halted the development of the project after the sensor we were working with could not go into mass production due to a critical flaw. As a result, we also terminated our contract with the sensor manufacturer with whom we had been collaborating. Further, we determined that the original sensor specifications would make it difficult to develop a product that will meet our and our customers’ high standards, and accordingly, we decided to go back to the drawing board.

We halted the development of the project after the sensor we were working with could not go into mass production due to a critical flaw. As a result, we also terminated our contract with the sensor manufacturer with whom we had been collaborating. Further, we determined that the original sensor specifications would make it difficult to develop a product that will meet our and our customers’ high standards, and accordingly, we decided to go back to the drawing board.

Kazuto Yamaki: Chief Executive Officer, SIGMA Corporation

At present, we are fully engaged in the research and development of the project, led by our head office, and are reviewing specifications to ensure that we will be able to satisfy the expectations placed on this project. While we have not proceeded to the development of a camera body yet, we will continue to do our utmost to create a camera in which we have full confidence.”

While we have not proceeded to the development of a camera body yet, we will continue to do our utmost to create a camera in which we have full confidence.

Kazuto Yamaki: Chief Executive Officer, SIGMA Corporation

Summary

Obviously, it will take some time until we see a production model of a Sigma camera armed with the full-frame Foveon X3 sensor. The concept of the Foveon X3 to imitate how film cameras capture light is blessed, and personally, I have a feeling that Sigma will solve and attack the numerous issues related to manufacturing the sensor. But again, it will take time. We’ll keep you posted regarding the development process.