all seems a very irrelevant measuring thing to me.I have bought lamps that are supposed to be 2 million candlepower that are not as good as ones that are 1 million.Think it is all down to refelector design etc.You can get one that is a a million using the same watt bulb as one that is 2 million.Some diy shops even sell them that claim to be 5 million still using the same bulb