Minimal and Maximal Eye Relief | Optics Trade Debates

By Polona Kraner Aug 1, 2018

Welcome to Optics Trade debates. In each episode, we talk about a different topic and try to answer the most common questions we receive about it. Today, we are going to talk about the minimal and maximal eye relief.

Eye relief is the distance between the eyepiece and the point at which a user has to place their eyes to see a clear image. So, it’s the distance from the eye to the lens of the eyepiece. This value goes from 70 mm to 120 mm on rifle scopes and from 12 mm to 24 mm on binoculars.

Eye relief on binoculars and spotting scopes is most important for people who wear glasses and a lot less for people who don’t. We would say that everything above 18 mm is a good eye relief. Eye relief on binoculars also affects the comfort of use.

Binoculars are fixed magnification so they only have one eye relief. With variable magnification, the eye relief can change and it depends on the magnification setting. This is where minimal and maximal eye relief come in to play.

On our web store, we state minimal and maximal eye relief on all optics that have variable magnification. We demonstrate the difference between the minimal and maximal eye relief in the video. The eye relief is longer on low magnifications and shorter on high magnification.

We would say that a good eye relief on rifle scopes starts at 90-100 mm. Everything above 100 mm is extended eye relief for safari hunters that use rifles with big recoil. If the eye relief is too short, the scope can hit the user when the rifle recoils.

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Explanation of the terms on our webpage:

Minimal eye relief is a minimum distance between the eye and eye-piece lens (rear of the scope, some manufacturers call the eyepiece ocular). For safety reasons, due to the recoil of the rifle, minimum eye relief for rifle scopes has to be at least 80mm. Larger rifle calibers produce higher recoil, so it is advised to have a minimal eye relief of 90mm or even more. Due to safety reasons, new rifle scopes have longer eye relief than older. Longer eye-reliefs were achieved with an advance of optical technology. The eye relief slightly changes when changing magnification and usually the eye relief is bigger at small magnifications and smaller on big magnifications. The difference is usually 10 millimeters or less.

Because of safety reason, some rifle scopes for safari rifles have extended eye-relief of more than 120mm. Scout and pistol scopes more than 500mm eye-relief, since they are usually mounted far away from the user.

Safety should always be on 1. place when handling guns and shooters often ignore, so make sure that you don`t get a »black eye« injury and choose the scope with a minimal eye relief of at least 80mm.