focal length crop mark

Others have suggested being able to import or use the exif data on focal length used by a particular camera when cropping. As Capture One knows which camera I shot with, then it should be able to show me, via the crop tool, the specific crops for various focal lengths, either by entering the focal length or, as previously suggested, via exif. For example, if I shoot with the Fujifilm GF 23mm (which has an 18mm full frame equivalent angle of view), but would like to see the crop of a 30 or 45mm lens, I currently have to guess. If C1 read the exif data, and offered an option within the crop tool to mimic a different focal length by entering it into a "custom aspect ratio" box, but instead of a different aspect ratio it is a different magnification, essentially.