Canon EF 200-400mm f/4L IS USM Extender 1.4X User Manual - Page 19

11. Infinity Compensation Mark Infinity compensation mark 12. Hood Lock knob Distance index To compensate for shifting of the infinity focus point that results from changes in temperature. 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 focusing in MF on subjects at infinity distance, look through the viewfinder or at the camera's LCD display while rotating the focusing ring. The special hood that comes with this lens cuts out unwanted light and protects the front of the lens from rain, snow, and dust. To attach the hood, loosen the hood lock knob by turning it counterclockwise. Fit the hood onto the lens's hood mount, and tighten the lock knob to fix it in place. Use the same procedure, in reverse, to remove the hood. ENG-18