One famous tourist sight right in the centre of Oxford is the Radcliffe Camera. Of course, the Radcliffe Camera isn’t a photography machine but a large 18th century building that is part of the Oxford University library. The origin of camera in the sense of a structure is a lot clearer than why camera now mostly refers to a photo-taking device.
The old sense that we don’t hear very much literally means ‘vaulted building’. It comes, like the French chambre and the more common English chamber, from Latin camera meaning ‘vaulted room’ and ultimately from Ancient Greek kamara.
Meanwhile, various clever people were working on the precursor to photography, using a pinhole device and a darkened room. This clever device needed a clever word and Latin’s always good for that; they put together the two words camera and obscura to make camera obscura, literally a dark room. The term’s first use is attributed to the German astronomer Johannes Kepler in 1604.
When photography kicked off in the 1840s, camera obscura was clipped, to refer to the new picture-taking devices. So essentially, when you’re taking a few snapshots, you’re actually using a ‘room’.