To date, we have developed various types of 8K cameras while considering the trade-off between cost and performance at each period of development. Our first 8K camera employed four 4K image sensors. This was followed by a second model, which used an 8K single-chip colour image sensor with the Super 35 optical format, thus offering compatibility with digital cinema lenses.
These cameras have been used effectively in a wide range of applications, such as covering and recording international sport events and entertainment programs as well as producing programs for 4K/8K test broadcasting, beginning in 2016.
In preparation for both the 4K/8K broadcasting starting in 2018 as well as the 2020 Olympic Games in Tokyo, we have reconsidered which parameters should be seen as the most important ones for 8K broadcast cameras, and we have also reviewed the appropriate elemental technologies for these cameras. In light of the technological advancements that have been made, we decided to develop a three-chip 8K camera with 5/4-in image sensors.
The camera we developed supports both high dynamic ranges and high frame rates, and we succeeded in reducing its size to that of an HDTV camera. Both its signal-to-noise ratio and its sensitivity achieved the best performances of all 8K cameras.
This paper discusses both the parameters and the elemental technologies of all of the 8K broadcast cameras that we have examined. It then continues to describe the characteristics of a new camera that we have developed and demonstrates its superior practical performance.
In August of 2016, we began test broadcasting based on the “8K Super Hi-Vision” format (referred to as “8K” hereafter) via a broadcasting satellite. Starting with broadcasts from the 2016 Summer Olympics in Rio de Janeiro, a variety of fascinating events, unique to 8K, were broadcast each day.
In the course of developing various cameras for handling the production of 8K programs in a wide range of genres, we have been developing both cameras that can output live streams as well as cameras with built-in recording devices that can handle on-location filming while also emphasising mobility.
In addition to achieving the results of our efforts to date, we switched from using the dual green (DG) format  which is the same as Bayer pixel arrangement to using the YCbCr422 format in pursuit of higher picture quality. Furthermore, we converted the optical design from the single-chip style to the three-chip style, and we also succeeded in raising the sensitivity by increasing the camera’s light use efficiency.