There’s an adage in photography: spend money on good glass. Translation: buy good lenses. I heard that early on and nodded like I understood. I did not understand.

Then I took a lens that started at f/5.6 into the rainforest to photograph a sloth. Yes, a sloth. The animal famous for not moving. The light was dim and green and filtered, and my camera did what cameras do when you ask them to perform miracles. ISO went up. Then it went up again.

When I got home and opened the files, the sloth was blotchy and noisy in a way I couldn’t unsee. That was the moment I stopped thinking “good glass” was a fancy-person suggestion and started treating it like basic math. Less light in the lens means more compromise everywhere else.