Is there is any Hadith about the limit of cutting beard?

From my knowledge I am not read or learn any Hadith about the limit of beard. I have a little beard. Some people says that you must want to put beard that define limit of four Imam. But I disagree(Ikhtilaf) with them. Can I Reject the rules of them? Is there is any Hadith about the limit of beard? Any further lecture on beard from (S.A.W) or any of his Companian?