Sidenote: the only meaning of “full frame equivalent aperture” is depth of field. It goes like
If you want the same field of view and depth of field (“bokeh”) as what you would get on a FF camera with a 100mm f2.8 lens, but on a micro four thirds body (2x crop factor), you will need a 50mm f1.4 lens. (Half the focal length, half the aperture)
You can say now that your 50mm has a “FF equivalent aperture of f2.8 on M43”, but that’s a horrendously incorrect and misleading wording of the actual settings
Sidenote: the only meaning of “full frame equivalent aperture” is depth of field. It goes like
If you want the same field of view and depth of field (“bokeh”) as what you would get on a FF camera with a 100mm f2.8 lens, but on a micro four thirds body (2x crop factor), you will need a 50mm f1.4 lens. (Half the focal length, half the aperture)
You can say now that your 50mm has a “FF equivalent aperture of f2.8 on M43”, but that’s a horrendously incorrect and misleading wording of the actual settings