GPO USA 6-24x50 Passion 4X Riflescope (MOA Ballistic Reticle) - Manual (Page 24)

Parallax Compensation
Since the reticle image and the target image are on different
focal planes, it is difficult for the eye to reproduce both images
at different distances sharply. Therefore, select riflescopes are
equipped with parallax compensation for long distances and
higher magnifications. Parallax adjustment will join these 2 images,
making a single sharp target and reticle image at the same time.
Therefore, you will need to adjust the sharpness of the reticle first
with the ocular diopter ring. Then, you will need to adjust the
parallax which will sharpen the target image to meet the reticle
image. Riflescopes with no parallax compensation are adjusted to
100 meters/110 meters.
Adjustment of the riflescope image,
riflescope without parallax compensation
Select an object and look through the riflescope. Use the highest
magnification on the riflescope during this process. Turn the
diopter adjustment (ocular focus ring) to make the reticle sharp.
Focusing the riflescope at the highest magnification will always
provide a sharp reticle at the lower magnification range.
Riflescopes with no parallax compensation are
adjusted to 100 meters/110 meters.
Image Position 1
Diopter setting