The whole thing is quite confusing, it would be nice if everyone would use crop factor or just publish the sensor dimensions instead.
I wholeheartedly agree. The present designation is much too confusing to the serious photographer who wishes to make a comparison, let alone the average consumer. It's high time for camera maunfacturers to state in clear, unambiguous language the size of their sensor, whether it's in dimensions, both width AND height (in mm) or, better yet , expressed as area [i.e., mm2 (squared)].
1D iii (x2), 1DS iii (x3), 6D, 16-35L ii, 24-105L, 70-200L IS ii, 24/3.5 TS-E, 40/2.8 STM, 50/2.5, 100/2.8L IS, 135/2L, 300/2.8L, 500/4L IS, 430EX II, EF 1.4x ii, EF 2x iii