From Daguerreotype to Modular: A Brief History of Interchangeable Lens Systems

That click is the sound of possibility. One moment I’m shooting a tight macro shot with my Sigma 105mm, the next I’ve snapped on my 24mm Art lens for a wide environmental portrait. This freedom is the foundation of modern photography, yet it was anything but a given.

The Short Answer: Interchangeable lens systems evolved from crude, single-purpose screw threads in the 1800s to standardized bayonet mounts in the mid-20th century, which then became electronically supercharged with the advent of autofocus. The modern mirrorless era, with its short flange distance, offers superior optical design and near-universal adaptability.

One Box, One Vision

Let’s go back to the beginning. The earliest cameras, like the Daguerreotypes, were integrated units. The lens was part of the box. There was no ‘system.’ If you wanted a different field of view, you needed a different camera, or at best, a different front element you could painstakingly unscrew and replace. It was slow, clunky, and utterly impractical for anything outside a controlled studio.

This was photography at its most fundamental. It reminds me of my first years in a print shop. You had one machine set up for one job. Changing anything—the paper stock, the ink, the plates—was a major operation. The early camera was the same: a single-purpose tool.

The Mount Creates the Market

The first real breakthrough came with the screw mount, most famously the Leica M39 thread mount introduced in the 1930s. This was revolutionary. For the first time, a standardized connection meant a lens from one manufacturer could reliably fit on a camera from another. It created an ecosystem.

But screwing a lens on and off is still slow. The real game-changer was the bayonet mount, which allowed for a quick twist-and-lock connection. Companies like Exakta were early pioneers, but the concept was perfected by the major players. Think of the legendary Nikon F-mount, introduced in 1959. It was so robust and well-designed that it remained the standard for Nikon SLRs for over 50 years, a testament to its engineering. That kind of longevity is almost unheard of in tech.

When the Lens Started Talking

The next great leap wasn’t mechanical, but electronic. With the rise of autofocus in the 1980s, the lens and camera needed to communicate. This sparked one of the biggest format wars in photographic history.

In 1987, Canon made the brutally decisive choice to abandon its old FD mount and launch the all-electronic EF mount for its EOS cameras. It was a massive gamble, making all their previous lenses obsolete overnight for new bodies. But it gave them a huge technological advantage. The wide electronic-only mount had no mechanical compromises and was built for the future.

Nikon, my brand of choice, took a more conservative path. They kept the F-mount but added electronic contacts and a mechanical ‘screw drive’ to operate the autofocus in the lens. It was a move that valued backward compatibility but, for a time, put them a step behind Canon’s lightning-fast and silent USM lenses.

I learned this lesson the hard way. Early in my DSLR days, I got obsessed with adapting old, cheap manual focus lenses. I bought a flimsy M42-to-Nikon adapter for a vintage lens I found for next to nothing. The idea was to get ‘character’ on a budget. The reality? The adapter had terrible tolerances, my focus was never truly sharp, and I missed critical shots during a live event fiddling with it. I wasted time and money trying to hack a solution instead of investing in the right tool for the job. A solid mount and a native lens are a system for a reason.

The Mirrorless Revolution: It’s All About the Flange

Ditching the mirror box in modern cameras did more than just make them smaller. It fundamentally changed lens design by drastically shortening the flange distance—the space between the mount and the sensor.

This is the magic of my Nikon Z6 III and its Z-mount. That short distance and wide diameter give optical engineers freedom they never had with DSLRs. It allows for sharper lenses, especially in the corners, and more radical designs. It also, ironically, makes adapting old lenses *better* than ever before. With a simple electronic adapter, I can use old F-mount glass on my Z body with full autofocus and aperture control. The new mount unlocked the potential of the old.

Beyond the Lens: The System is Everything

Today, the concept of ‘interchangeable’ has exploded. We don’t just swap lenses. We build entire rigs. My camera body is often the core of a setup that includes a SmallRig cage, an external monitor, microphones, and a gimbal like my Zhiyun Crane 4. Modularity is the new standard.

The lens mount was the first step, the gateway to a world where the camera is not a fixed object.

The Bottom Line

• Standardization Was Key: The move from proprietary optics to standardized mounts like the M39 and F-mount created the entire third-party lens market and gave photographers choice.

• Electronics Changed Everything: The shift from mechanical linkages to electronic contacts for autofocus and aperture control was the most significant leap, turning the lens from a piece of glass into a smart peripheral.

• Mirrorless Isn’t Just Smaller, It’s Smarter: The short flange distance of mirrorless mounts is a fundamental optical advantage, enabling better lens designs and incredible adaptability for legacy glass.

That little button you press to release your lens is a portal through history. Every time you swap glass, you’re taking advantage of decades of fierce competition and brilliant engineering. Never take that click for granted.

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