The Stereoscopic Camera is a historical item which can be found by Anna in Ypres during Chapter 2.
Location[]
To the right hand side of the red floor, hit the painting to reveal a key then take it back to the ground floor. Push the drawers to the right then climb up them to get outside. Use the key to open the gate inside the shed, then grab this item from the alcove behind the painting.
Description[]
"A camera that captures two simultaneous images on glass plates, enabling relief images .
Use of the camera was relatively widespread because the device was small and readily transportable."