Curious about drop-in filters and how they fit into high-end lenses like the Nikkor Z 800mm f/6.3? When I first encountered them, I found little to no explanation about what they were or how they worked—until I got hands-on. In this article, I break down the mystery behind drop-in filters, show you how they function, and share tips on where to find replacements. Whether you’re a wildlife or astronomy photographer, this guide will help you get the most out of your gear. Click to learn more!