4K resolution
The term "2160p" could be applied to any format with a height of 2160 pixels, but it is most commonly used in reference to the 4K UHDTV resolution of 38402160 due to its association with the well-known 720p and 1080p HDTV formats. Although 38402160 is both a 4K resolution and a 2160p resolution, these terms cannot always be used interchangeably since not all 4K resolutions are 2160 pixels tall, and not all 2160p resolutions are ≈4000 pixels wide. However, some companies have begun using the term "4K" to describe devices with support for a 2160p resolution, even if it is not close to 4000 pixels wide. For example, many "4K" dash cams only support a resolution of 28802160 (4∶3); although this is a 2160p resolution, it is not a 4K resolution. Samsung also released a 51202160 (64∶27) TV, but marketed it as a "4K" TV despite its 5K-class resolution.
Red Digital Cinema
The early team members engaged in undisclosed research on how to make a digital camera feasible for Hollywood productions. Part of this involved using 4K resolution instead of 2K which was most common at the time. Another technical hurdle was to achieve the focusing quality of DSLR cameras without sacrificing frame rate. Part of Red's solution to this problem was developing a sensor with a physical size comparable to that of analog film. At the 2006 NAB Show, Jannard announced that Red would build a 4K digital cinema camera, called the Red One, and began taking pre-orders.