Sigma's the only company that announced a full-frame mirrorless camera in 2018, but it hasn't started selling it. at Photokina in September, it didn't provide much detail save to say it would be out this year. Now that's slipped to 2020, but the company did state a resolution for the new version of its Foveon sensor: 60.9 megapixels.
Foveon sensors have always had smaller spatial dimensions than typical sensors using a Bayer color filter array, which has historically put them at a "moar pixels" marketing disadvantage.
A Bayer array mosaics the red, green and blue filters so that for every block of four pixels, one's got a red filter, one a blue and two have green. The Foveon sensor, in contrast, is composed of red-, green- and blue-sensitive layers. It uses those to create a luminance channel (that's the image detail), which is then combined with the color data to form the full-color picture.
Sigma math -- in which the company defines a "pixel" as a single color element rather than an actual picture element -- takes the 20-megapixel spatial dimension of the new sensor (5,520x3,680) and multiplies it by the number of layers to derive its 60.9-megapixel figure. So () while the Foveon sensor might deliver better color and detail than other sensors with similar numbers of pixels, the spatial resolution of the final files is represented by the lower numbers, in this case, 20 megapixels.
It's kind of a reverse of the type of pixel-binning that's used by thewhich takes a 40-megapixel sensor and aggregates each group of four pixels into an uberpixel with increased light sensitivity, resulting in a 10-megapixel photo.
2018 was a big year for full-frame mirrorless announcements:, and and Sigma (via the L-Mount alliance) all jumped into what previously had been sole domain.
Sigma declined to comment.
Originally published 8:40 a.m. PT.
Update, 11:40 a.m. PT: Adds Sigma's response to our request for comment.