The Sony α7
October 2013 (α7 and α7R)
The first full-frame mirrorless interchangeable-lens cameras: full-frame sensors in small bodies with electronic viewfinders. Within five years Canon and Nikon followed.
How it began
Mirrorless cameras dropped the reflex mirror of the SLR and showed the sensor’s live image on a screen or electronic viewfinder. Panasonic’s Lumix G1 (2008) was the first with interchangeable lenses, using a smaller Micro Four Thirds sensor. In 2013 Sony put a full-frame sensor in a mirrorless body: the α7.
How it works
Without a mirror box, the lens mount sits close to the sensor, so the body can be small and the lenses compact. The sensor runs all the time, feeding the electronic viewfinder, autofocus and exposure systems directly, with a preview of the final exposure.
Why it mattered
The α7 showed that full-frame quality need not come in a big SLR. Sony’s market share grew, and in 2018 Canon and Nikon launched full-frame mirrorless systems, ending the long reign of the reflex mirror that began with the Nikon F.
Limits and what replaced it
Early models had short battery life and laggy viewfinders, and the lens range was small at first. Later generations improved all of these, and stacked sensors brought very fast readout.
Today
Its successors are widely used; Canon and Nikon both moved to full-frame mirrorless in 2018.