So then there would be a difference between magnification and reproduction ratio then?
Saying 1:1 is not the same as 1x?
Magnification and reproduction ratio mean the same thing, they're just different expressions of the same principle..... the size of the projected image on the film/sensor in relationship to it's actual size.
1:1 rr = 1x mag.
2:1 rr = 2x mag.
1:2 rr = 0.5 mag.
But sensor / film size doesn't enter into it. A 10mm object, projected onto the film / sensor at 10mm, is still a 1:1 (or 1x), whether it's a cell phone camera or an 8x10 view camera.