English to Spanish Tech/Engineering Photography/Imaging (& Graphic Arts)

Hello to everyone!

I'm looking for an appropriate translation of the term "crop factor" into spanish language. The definition of this term according to http://www.cambridgeincolour.com/ is the following:

"The crop factor describes the sensor’s width ratio to a full-frame 35 mm sensor. It is called this because when using a 35 mm lens, such a sensor effectively crops out this much of the image at its exterior (due to its limited size)."

I would be pleased if you have any suggestion.

Thanks in advance!