Canon EOS C300 Mark II CINEMA RAW DEVELOPMENT INSTRUCTION MANUAL Version 1.4 M - Page 10

The viewfinder guiding indicator is a white colored cursor which can be positioned anywhere within the focusing area that constitutes an 80% horizontal and 80% vertical region of the onscreen image display - as shown in Figure 13. The guide cursor is moved by the cinematographer to overlay the specific subject within the scene that is to be sharply focused. Allied with the guiding indicator are the three small arrows that lie above the cursor, and their direction is an unambiguous signal as to which direction the cinematographer should rotate the focus control. Precise focus is achieved at the point where the guide cursor snaps to a vivid green color. Figure 13 On top is a replication of the viewfinder display within which is a cursor that can be positioned over most of the image area (red line boundary shown). The lower illustration shows the guide cursor detail which uses three arrows to indicate the direction to rotate the focus control. At the point of precise focus on the chosen subject the cursor snaps to a green color. Instead of struggling to identify sharp focus on a selected subject in a small viewfinder, attention is instead solely directed to the cursor overlaying that subject. The precision focus detection takes place within the CMOS image sensor photosites encompassed by that cursor thus ensuring absolute precision of focus achievement. Nothing has been taken away from the cinematographer (other than the vexation of sharpness limitations in the viewfinder). The principle of the phase detection used is very similar to that described in an earlier Canon paper on an optical embodiment within a broadcast television lens [3]. 9