Due to viewers' desire for larger TVs with more faithful content reproduction, there has been a need for an increase in resolution, i.e., the number of pixels a TV can display. Therefore, UHDTV standards were introduced, defining resolutions that far exceed the currently widely accepted HDTV norm. This paper provides an overview of the development of relevant standards and accompanying technologies, from analyzing factors influencing the definition of their parameters to addressing implementation issues and technological solutions. The focus is on the UHDTV1 standard (4K), which defines a resolution of 3,840x2,160 pixels, with a frame rate of up to 120 frames per second, progressive scanning, and square pixels. This is accompanied by new color spaces with a wider gamut and a large dynamic range (HDR), featuring relative HLG (Hybrid Log-Gamma) for live content production and absolute PQ (Perceptual Quantizer) gamma, optimized for pre-recorded movies and TV content. To meet the parameters of the UHDTV1 standard, new image sensors have been developed. The paper explains the parameters and principles of image sensor operation down to the level of photoelements, compares CCD and CMOS sensor technology, different methods for color recognition (RGB prism with three sensors, Bayer filter), discusses the issue of a rolling shutter, and provides an overview of several sensors used in UHDTV1 television cameras (Grass Valley's 2/3" Xensium-FT and Xenios sensors) and several Super 35 and full-frame sensors used in Canon cinema cameras. Although the availability of UHDTV content is still limited, and many viewers do not have devices capable of displaying content in 4K resolution, it is crucial that standards have been established to enable UHDTV implementation in both defined resolutions (4K and 8K). Consequently, an increasing availability of UHDTV content and a more widespread opportunity to view such content can be expected over time.