OpticVerdict

What is parallax in a rifle scope?

DR By Dale Renner, Optics reviewer and outdoors writer at OpticVerdict.
Plain-English guide · Updated 2026-07-03

Quick answer: parallax is when the reticle appears to shift against the target as you move your eye, because the target image and the reticle are not on exactly the same plane inside the scope. It is eliminated at the scope’s set parallax distance. Fixed-parallax scopes (usually set at 100 yards) are fine for most hunting; you only need adjustable parallax (a side focus knob or adjustable objective) for precision rimfire up close or long range at high magnification.

How parallax shifts the reticle when your eye moves Left: when the reticle plane and target image plane are apart, two eye positions see the reticle land on different spots, an apparent shift. Right: when the planes coincide at the focused distance, both eye positions see the same aim point. Parallax present Parallax removed reticle plane target image eye high eye low shift planes together same aim point Move your eye behind the scope: if the reticle drifts on the target, parallax is present. Focus the side knob until it locks still.
Why the reticle appears to move: the reticle and the target image sit on different planes until the scope is focused for that distance.

What parallax actually is

Inside your scope the target image is focused onto a plane, and the reticle sits on its own plane. When those two planes do not perfectly coincide, moving your eye off the center of the eyepiece makes the reticle appear to slide across the target, even though nothing has moved. Aim with your eye a little high and the shot goes one way; a little low and it goes the other. At the distance the scope is focused for, the planes line up and the shift vanishes. The effect is small at low magnification and short range and grows at high magnification and at distances far from the focus setting.

Fixed parallax vs adjustable parallax

Fixed parallax scopes are set at the factory, almost always at 100 yards (some rimfire models at 50 or 60 yards). They are simpler, lighter and cheaper, and for centerfire hunting inside a few hundred yards any residual shift is tiny as long as you keep a consistent cheek weld. Most 3-9x hunting scopes are fixed parallax for exactly this reason.

Adjustable parallax comes as a side focus knob (common on modern scopes) or an adjustable objective (AO) ring on the front bell. It lets you dial the image sharp and parallax-free at any distance. This matters in two cases: precision rimfire, where tiny targets are engaged from 25 to 100 yards, and long range at high magnification, where a small shift becomes a real miss. It also lets the same scope focus down very close, which is why long-range scopes with low minimum parallax double as rimfire trainers.

How to remove parallax

  1. On an adjustable scope, turn the side focus or objective until the target looks crisp.
  2. Move your head slightly up, down and sideways behind the eyepiece.
  3. If the reticle stays locked on the same spot, parallax is gone. If it drifts, fine-tune the knob and repeat.
  4. On a fixed-parallax scope, just keep a repeatable, centered cheek weld; that alone keeps any shift negligible at hunting ranges.

Which of our picks have adjustable parallax?

FAQ

What is parallax on a rifle scope?

Parallax is an optical effect where the target image and the reticle sit on slightly different planes inside the scope, so the reticle appears to shift against the target when your eye moves off the center of the eyepiece. At the scope’s set parallax distance the two line up and the shift disappears. It matters most at high magnification and at distances far from where the scope is focused.

Do I need an adjustable parallax scope?

Not for most hunting. Fixed-parallax scopes are set at the factory (commonly 100 yards) and are perfectly accurate for centerfire hunting inside a few hundred yards. You want adjustable parallax (a side focus knob or adjustable objective) if you shoot precision rimfire at close range, or long range at high magnification, where you engage targets at widely varying distances.

How do I remove parallax?

On an adjustable scope, turn the side focus or objective ring until the target image is crisp, then move your head slightly behind the eyepiece; if the reticle stays put on the target, parallax is gone. On a fixed-parallax scope you simply keep a consistent cheek weld and centered eye position, which minimizes any shift.

What parallax setting do our picks use?

Our two hunting picks are fixed-parallax: the Vortex Crossfire II 3-9x40 is set at 100 yards and the Leupold VX-Freedom 3-9x40 has fixed parallax. Our long-range picks have adjustable side focus: the Diamondback Tactical 6-24x50 focuses from 10 yards to infinity and the Strike Eagle 5-25x56 from 15 yards, which is why they double as precision rimfire scopes.

Dale Renner · Optics reviewer and outdoors writer at OpticVerdict

Every award, spec and superlative in this guide is checked against a primary source before it is published, and every rating we cite is shown attributed to where it comes from. Read how we evaluate or learn more about this site.

Source-verified claims Attributed ratings only Method disclosed on every page

Related: FFP vs SFP · MOA vs MRAD · how to mount a rifle scope · best rifle scopes 2026.