Eye relief
How far your eye sits behind the eyepiece and still sees the full picture. On a rifle scope, more distance keeps the scope off your face under recoil.
What it means
Eye relief is the distance from the back of the eyepiece to your eye at which you see the whole image. Thermal and night vision scopes publish it in millimeters. In the scopes on this site it runs from about 45 to 90 mm (roughly 1.8 to 3.5 inches). Many conventional day scopes give about 3 to 4 inches.
What it changes in the field
On a rifle, eye relief is a safety and comfort spec. Too little and the eyepiece can hit your brow when the rifle recoils, especially shooting uphill or from an awkward sitting position on a stand. More relief gives room for that movement.
Many thermal scopes use a soft rubber eyecup that you press close to the eye. That blocks the screen’s glow from lighting up your face and keeps the picture steady, but it also means the scope is designed to be close. On a hard-recoiling rifle this matters more.
Eye relief also decides how you set the scope on the rifle. Thermals often end up mounted higher and farther back than a day scope, which affects cheek weld. See mount.
What to look for
- For magnum calibers or shotguns, longer eye relief is more comfortable.
- On night vision monoculars and goggles, eye relief also matters if you wear glasses.
- Check the recoil rating together with eye relief.
How we use it on this site
We show the maker’s figure for riflescopes and score more as better.