Using the Infinity Compensation Mark on the EF 400mm f/4 DO IS USM lens
Article ID: ART174659

Date published: 06/03/2019

Date last updated: 06/03/2019
Description
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 mark is aligned with the distance index.
Solution
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 mark is aligned with the distance index.
For accurate focusing in MF on subjects at infinity distance, look through the viewfinder while rotating the focusing ring.