Canon EF 70-300mm f4.5-5.6 DO IS USM - Manual (Page 11)

ENG-10
8. Infinity Compensation Mark 9. Infrared Index
Infinity compensation mark
Distance index
The infrared index corrects the focus setting
when using monochrome infrared film. Focus on
the subject manually, then adjust the distance
setting by moving the focusing ring to the
corresponding infrared index mark.
• The infrared index position is based on a
wavelength of 800 nm.
• The compensation amount differs depending on
the focal length. Use the indicated focal length as
a guide when setting the compensation amount.
• Be sure to observe the manufacturer’s
instructions when using infrared film.
• Use a red filter when you take the picture.
Some EOS cameras cannot use infrared film. See
the instructions for your EOS camera.
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 L mark is
aligned with the distance indicator on the
distance scale.
For accurate manual focusing on subjects at
infinity distance, look through the viewfinder while
rotating the focusing ring.
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