Really, there is no shooting accessory that swims in more intricacies than scopes. Even the simplest examples of indispensible devices have a number of concepts that must be grasped to get the most out of them. More and more, a facet that has confronted shooters is choosing between a first and second focal plane scope. Mechanically speaking, the difference is purely where the reticle is located in the erector lens assembly. If it’s in front of the assembly, toward the objective lens, then the reticle is on the first focal plane; if it’s at the rear, toward the eyepiece then it’s on second focal plane. It’s a pretty simple concept, but as the above video from Vortex Optics shows it has a huge impact on how variable-power scopes operate. And if you are in the market for an optic, it is most definitely an aspect of which you’ll want a firm grasp. Each has its pros and cons, of which shooters should carefully weigh before dropping hard-earned cash on an accessory that can cost a small fortune.