Canon EF 16-35mm f/2.8L III USM EF16-35mm f/2.8L III USM Instructions - Page 9

4. Infinity Compensation Mark 5. Infrared Index Distance index Infinity compensation mark To compensate for shifting of the infinity focus point that results from changes in temperature, there is a margin at the infinity (∞) position. The infinity position at normal temperature is the point at which the vertical line of the distance scale L mark is aligned with the distance index. For accurate manual focusing of subjects at infinity, look through the viewfinder or look at the magnified image* on the LCD screen while rotating the focusing ring. * For cameras with Live View shooting capability. Infrared Index The infrared index corrects the focus setting when using monochrome infrared film. Focus on the subject manually, then adjust the distance scale indicated by the distance index by moving the focusing ring to the corresponding infrared index mark before shooting. 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. ●● The compensation amount differs depending on the focal length (large at the wide end, small at the telephoto end). Use the 16 (mm) infrared index position as a guide when setting the compensation amount manually. ●● Be sure to observe the manufacturer's instructions when using infrared film. ●● Use a red filter when you take the picture. ENG-8