Specifying the ratio with [] and []

Press [Reduce / Enlarge].

Press [Direct. Mag. %].

Press [[] [] keys].

Press [Horizontal].

Adjust the ratio using [] and [].

Pressing [] or [] changes the ratio in increments of 1%. Pressing and holding down [] or [] changes it in increments of 10%.

Press [Vertical].

Adjust the ratio with [] and [].

Press [OK] twice.