I talked about magnification in close-up photography and I said I would explain a bit about its figures and how they relate.
The figures compare the actual size of an object in relation to its size reproduced on the CCD sensor. This can be seen as a ratio (1:1/2), or as fractions (1/2x or .05x). X = lifesize.
Lifesize is where the size of the object is the same as its size portrayed in an image. Therefore, 1/2x or 0.5x shows the object to be half life its actual size so it would appear to be half its size when represented on a photograph. The ratio theory (1:2) means the same thing.
So in other words, 1:1 is life size on the sensor. The same as 1x or 1.0x, but 1:2 is half its size on the sensor. The same as 1/2x or 0.5x, or 2:1 would indicate the object appears twice as large on film.
I hope that has enlightened you.