Traditional Culture Encyclopedia - Photography major - What is the sign that the camera is used for portrait photography to become a reality?

What is the sign that the camera is used for portrait photography to become a reality?

Cameras were used for portrait photography until 1840, when Walcott of new york invented the "mirror camera". This improved wooden camera has an opening in the front of the box, which illuminates the incoming image on a large concave mirror and then reflects it on a photosensitive plate about 5×6 cm. The final picture, though smaller, is brighter.