Parallax
Also called: parallax adjustment, side focus, adjustable objective
An apparent shift of the reticle against the target when your eye is off center. Most hunting scopes are set so it disappears at one distance.
- Type
- Specs & Terms
- Typical setting
- Many hunting scopes are set for about 100 yards
- Adjustable
- Side-focus knob or adjustable objective on some scopes
- Effect
- Can cause aiming error at other distances, especially at high power
- Used for
- Hunting, Target shooting
What it is good for
- Understanding why a group walks as you move your head.
- Aiming precisely at long range.
- Using high magnification.
Where it falls short
- Little effect at short range on low power.
- Adjustable parallax adds cost and parts.
- Good shooting form lowers its effect.
Tips
- Keep your eye centered behind the scope and check the target while moving your head slightly.
Works well with
- Variable-Power Scope: where it shows up most at high power.
Field notes
If the image and the reticle are not on the same focal plane, moving your eye makes them appear to slide against each other.
Related guides
Specs here are typical, not guarantees; models differ, so check the maker's published numbers. Never look at the Sun through any optic without a certified solar filter, and zero or mount a scope with the firearm unloaded and pointed in a safe direction. Rules on optics, such as scopes on certain hunts or lasers and electronics, differ by state; our state resources directory links to each state's official regulations. Want a buying guide? Read Choosing Hunting Optics.