Front Sight Focus
Keeping the eye sharply focused on the front sight rather than the target, a core fundamental of accurate iron-sight shooting.
Front sight focus is the discipline of putting the eye’s sharp focus on the front post while the target and the rear sight both go slightly soft. The eye can only truly focus on one distance at a time, and the front sight is the element where a small error has the largest effect on where the bullet lands. Shooters with iron sights train to let the target blur a little so the front post stays crisp through the moment the trigger breaks.
This habit supports clean sight alignment, because you cannot center a front post you are not actually looking at. It also steadies the wobble that every shooter sees, since a sharp front sight gives the eye a clear reference to settle on. With an aperture sight the rear ring helps the eye index automatically, which frees more attention for the front post and the final sight picture.