Candela was chosen so that the new definition would precisely match the old definition. Although the candela is now defined in terms of the second (an SI base unit) and the watt (a derived SI unit), the candela remains a base unit of the SI system, by definition. If a source emits a known luminous intensity "I" (in candelas) in a well-defined cone, the total luminous flux "Φ" in lumens is given by where "A" is the "radiation angle" of the lamp—the full vertex angle of the emission cone. For example, a lamp that emits 590 cd with a radiation angle
Vincent Candela taker. At club level, Candela played football in France with Toulouse (1992–95) and Guingamp (1995–97), before moving to Italian side A.S. Roma (1997–2005). He won one "scudetto" with Roma, as well as the Supercoppa Italiana, in 2001, also helping the club to the 2003 Coppa Italia Final. He later joined English side Bolton Wanderers (2005), before returning to Italy to play for Udinese (2005–2006), and Siena (2006–2007), as well as spending a spell on loan with Messina (2007). On 28 January 2007 he played his last Serie A match for Messina against Ascoli. For France, Candela was capped 40 times