Rangefinder cameras were first introduced in the 1920s as an alternative to bulky and complex SLR cameras. These cameras used a separate viewfinder that was coupled to the focusing mechanism, allowing the photographer to see outside the frame of the lens and accurately focus on a subject.
This split-image rangefinder usually is a range-finding focusing mechanism allowing the photographer to measure the subject distance and take photographs that are in sharp focus without a mirror. Most varieties of rangefinder show two images of the same subject, one of which moves when a calibrated wheel is turned; when the two images coincide and fuse into one, the distance can be read off the wheel.
Leica was the first company to introduce a successful rangefinder camera, the Leica I, in 1925. This camera became very popular among photojournalists and street photographers for its compact size, quiet operation, and high-quality optics.
In the 1950s and 1960s, other companies, such as Canon, Nikon, and Contax, introduced their own rangefinder cameras, offering a range of lenses and features for photographers to choose from. Rangefinder cameras continued to evolve, with improved viewfinders, faster shutter speeds, and more advanced light metering systems.