Autofocus
1977 (Konica C35 AF); 1985 (Minolta Maxxum 7000 SLR)
Cameras learned to focus themselves, first with rangefinder-like sensor modules in compacts, then with phase detection inside SLRs.
How it began
Focusing by hand was slow and easy to get wrong. In 1977 Konica’s C35 AF used a Honeywell module that compared two views of the scene, like an automatic rangefinder. In 1985 Minolta’s Maxxum 7000 brought fast autofocus to the SLR.
How it works
Phase detection splits light from opposite sides of the lens and measures how far the two images are shifted, which tells the camera both which way and how far to move the focus. Contrast detection moves the lens until fine detail is sharpest.
Why it mattered
It made sharp pictures of moving subjects routine and helped cameras sell to people who had never focused one.
Limits and what replaced it
Early systems hunted in low light and on plain surfaces. Modern cameras put phase-detection pixels on the sensor itself and use subject recognition to decide what to focus on.
Today
Every modern camera and phone focuses itself, often tracking eyes, animals and vehicles across the frame.