Canon TS-E 90mm f/2.8 TS-E45mm F2.8 Instruction Manual - Page 12

6. Depth-of-Field Scale (TS-E24mm f/3.5L) 7. Infrared Index (TS-E24mm f/3.5L) The depth of field is the distance in front of and behind the plane of focus on the subject that appears sharp. The depth of field is indicated by the area between the depth-of-field scale lines below the distance scale. The numbers on the scale are F values, and for example, if the shooting distance is 1.5 m and the aperture is f/8, the area in focus will extend from about 1 m to 3 m. ● The depth-of-field scale is only valid when the tilt scale is set to the "0" position. ● The depth-of-field scale is an approximate indicator. The infrared index corrects the focus setting when using monochrome infrared film. Focus on the subject in MF, then adjust the distance setting by moving the focusing ring to the corresponding infrared index mark. Some EOS cameras cannot use infrared film. See the instructions for your EOS camera. ● The infrared index position is based on a wavelength of 800 nm. ● Be sure to observe the manufacturer's instructions when using infrared film. ● Use a red filter also when you take the picture. ENG-11