What does "eye relief" refer to in scopes?

Eye relief specifically refers to the distance from the eyepiece of the scope to the shooter's eye. This measurement is crucial for ensuring that the shooter can see the full field of view without any obstruction and can do so comfortably, especially when recoil is considered. Having appropriate eye relief helps prevent injury to the shooter's face from the scope during firing, particularly with high-caliber firearms. This distance varies among different scopes, and a longer eye relief is often recommended for rifles with significant recoil or for users who wear glasses, as it provides a safer and more comfortable shooting experience.

While the other options touch on aspects related to using a scope, they do not correctly define eye relief. For instance, the distance from the target to the scope is not relevant to eye relief, and comfort while viewing is influenced by eye relief but does not define it. Similarly, optical magnification relates to how an image is enlarged rather than the specific distance from the eyepiece to the shooter's eye.