Ozgurdonmaz/Getty Images We may receive a commission on purchases made from links. Trends always come back around, especially fashion trends. That's not just an anecdote; there's math behind the phenomenon, and  trends seem to come back on a 20-year cycle . So, it probably shouldn't come as a surprise that your old film cameras are popular again. There's a really cool reason behind it, according to those who are on the hunt for the old tech. It moves away from the instant gratification of today's hyper-digital world, where phones and digital cameras can instantly show you what you captured. Instead, it's equal parts authentic and lived-in. Taking a traditional photo and developing it slows you down. "There's a romanticism behind it, a nostalgia," says one proponent to the BBC . Gen Z and Millennials are responsible for the surge in popularity of analog cameras. They're seeking authentic, unique experiences, which is something digital photography cannot really achieve on the same scale.…