Legacy glass still shines

Nice picture.

When using a legecy lens on a 4/3 camera, I understand the effective focal length factor is 2x, i.e., 90mm = 180mm. When using a legecy macro lens on a 35mm film camera, you can focus down to the magnification scale , e.g. 1:4, 1:3, 1:2, 1:1.

When mounted on a 4/3 camera, does the 2x factor apply? Does a designated magnification 1:4 becomes an effective 1:2? Does 1:1 become 2:1 or twice actual size?