Cinematography-Theory-And-Practice

Figure 9.5. Pixels on a screen. Theyare enlarged here to see detail. Theterm pixel is derived from picture element.All digital imaging is based onpixels.SHOOTING FORMATSDigital formats are defined either by how many horizontal and verticallines (or lines of pixels) they are composed of (such as 1080x1920or 720x1280 — usually classified as 1080 or 720) or by their resolutionas expressed in how many horizontal lines of pixels there are(such as 2K or 4K).What’s in a “K”?2K and 4K capture are rapidly becoming the standard for HD acquisitionin professional work. A 2K image is one that measures 2048(2K or 2x1024) pixels across horizontally. A 4K image measures4096 pixels across or 4x1024. By comparison, HDCam (a Sonyformat) is most frequently shot at 1080. 2K is slightly more resolutionthan 1080 and 4K is four times the resolution. The verticalmeasure of pixels may vary somewhat as not all frames or camerasensors share the same aspect ratio. “K” refers to kilo (one thousand)and 1024 is derived from binary code, the same as a kilobyte. A “K”is increments of 1024 pixels measured horizontally.2K, 4K and Higher Resolution FormatsThese types of video that offer higher resolution than the 1080 standardare referred to as 2K, 4K, 5K, 8K and so on. Some people callthese higher-resolution formats Super High Def. It is important toremember that this is a different way of describing a video format.720 and 1080 refers to the number of video lines measured vertically.(This is described in more detail later in this chapter after wetalk about formats.) For more detail on formats and aspect ratio, seethe chapter Professional Formats. The term format can refer to eitherthe type of camera (HD, DV, film, etc.) or the shape of the frame,which is aspect ratio; many HD video cameras can shoot in severaldifferent aspect ratios.DIGITAL COMPRESSIONDigital cinema cameras are capable of generating extremely largeamounts of data up to hundreds of megabytes per second. To helpmanage this huge data flow, nearly all cameras and the recordinghardware designed to be used with them utilize some form of compression.Prosumer cameras typically use high compression to makethe video files more compact for recording and storage. While thisallows footage to be comfortably handled even on smaller, less powerfulcomputers, the convenience comes at the expense of imagequality. The software is also constantly improving in its ability tohigh resolutions.cinematography152