Sony Semiconductor has published technical specs of the IMX472, a Four Thirds format Stacked CMOS sensor that can be read-out at full bit-depth at up to 120 fps. The super-fast readout of Stacked CMOS sensors is key to fast shooting and fast autofocus, as well as video capabilities in the latest high-end cameras.

The 21.77mm diagonal (4/3"-type) sensor would seem to be perfectly suited to underpinning range-topping cameras in the Micro Four Thirds system. Perhaps not coincidentally, OM Digital Solutions (maker of Olympus-branded cameras) and Panasonic are both likely to have new cameras on the horizon.

OM Digital Solutions has been publishing teasers about an online Announcement Event scheduled for October 27th. The accompanying graphic shows a mount swathed in mist, which could suggest a model at the pinnacle of its range. Or could simply be a reference to Mount Olympus.

OM Digital Solutions has something in the offing

Meanwhile, Panasonic's promised GH6 model is due soon. Panasonic has already said the camera will have a 'high speed sensor' capable of 4K/120 capture, which would fit with the IMX472 spec.

Panasonic also promises '10-bit 5.7K 60p video by taking full advantage of the newly developed Micro Four Thirds sensor,' which might imply a sensor with 5700 horizontal pixels. But, given Panasonic's track record of branding of 5184x3456 images as '6K' photos, it could be that 'taking full advantage of' refers to something like a nearly full-sensor 4:3 mode that uses the same number of pixels as a 5.7K video would, rather than 16:9 video with 5700 pixels. That's speculation, of course, but we wouldn't rule it out.

Either way, the existence of a public spec sheet for the IMX472 typically means it's already in volume production, and has probably been available to customers for some time.

The spec sheet says the sensor has 3.3μm pixels, which are likely to be of a similar design to the ones in the two existing 20MP sensors the company makes. The move to a stacked design sees the maximum readout speed for the whole sensor hit an impressive 121 frames per second in the maximum, 12-bit readout mode.

The sensor uses an ADC that can be operated at a maximum of 12 bits because 3.3μm pixels are relatively small, and the maximum amount of light they can capture can be fully encoded with 12 bits, once you account for noise. Use of a higher bit depth would just generate additional data about noise, rather than giving any improvement in image quality.

A teaser image of the forthcoming Panasonic Lumix DC-GH6 which, we can speculate, may feature the new 20MP Four Thirds sensor.

The variant of the sensor listed on the Sony Semiconductor site has a Quad Bayer color filter array, designed so that alternate lines of the sensor can be read-out at different times, giving two interleaved Bayer-like images for HDR capture, or allowing quartets of photodiodes to be binned, giving lower noise images.

That said, there are direct parallels between this Quad Bayer approach and Fujifilm's Super CCD EXR design, which offered resolution, dynamic range and low-light priority modes in a similar manner. In an age of social media sharing, it could be that low-noise and high DR 5MP images are seen as being valuable again.