If you’ve spent any time reading about photography, you’ve probably come across reverential mentions of Leica cameras and other “rangefinders” used by a lot of great street photographers like Henri Cartier-Bresson in the mid-20th century. I know I was confused when I first heard about them since they aren’t really around anymore, so here’s what they are.
The Original Mirrorless Cameras
Rangefinders are the original mirrorless cameras. They were popular with street photographers because they were a lot smaller and more unobtrusive than the bulky film SLR cameras available at the time. They used the same 35mm film as SLRs, but they had a different focusing method that didn’t need a mirror.
You probably have a rough idea how SLRs work if you’ve ever picked one up, but here’s a refresher. To manually focus an SLR (or DSLR), you look through the viewfinder. Light enters through the lens, and the camera’s mirror system reflects it into your eye. You then adjust the focus of the lens until everything is sharp. When you press the shutter button, the mirror lifts up, and the light hits the film instead, taking a picture. What you saw through the lens is pretty much exactly the picture you get.
Rangefinders use a different focusing method called, appropriately enough, a rangefinder. Instead of looking directly through the lens via a mirror, a rangefinder’s viewfinder is an entirely separate visual system mounted as close as possible to the lens. It shows two overlapping images of the subject. By aligning the images, the distance—or range—to the subject can be calculated (thanks to the parallax effect) and you can focus the lens.
The earliest rangefinder cameras required the photographer to focus the lens and find the range as two separate actions, but most of the popular models used by the likes of Cartier-Bresson paired the lens focus to the rangefinder mechanism.
One big problem with rangefinders is that what the photographer saw when they looked through the viewfinder didn’t exactly match the final photo because they were separate systems—it’s the same effect you get from a disposable camera. This didn’t really matter for street photography where size and portability were vital, but for other fields of photography, it was an insurmountable drawback.
This drawback, along with the fact that zoom lenses and telephoto lenses are next to impossible to design for a rangefinder camera, meant that they never really had a chance against SLRs and later DSLRs.
Leica—the manufacturer of the most famous and prestigious rangefinders—sells an insanely expensive digital rangefinder, but they’re the only one. It’s a beautiful camera and an excellent piece of technology, but there’s a reason that professional photographers don’t use it day to day.
Mirrorless cameras, however, are the spiritual successors to rangefinders. They have the same size and weight advantages over DSLRs but overcome the drawbacks of rangefinders with electronic viewfinders and live view screens.