LED lighting technology is enjoying a rapid development. 15 years ago, a LED street light with a power consumption of 1 watt can only sent out lights of 30lm. 15 years later, a one-watt LED light can have a luminous flux around 100lm (super high power LED). While a 15-watt filament lamp have a luminous flux about 180lm. The development of LED is so fast that it is really hard to replace a 15-watt filament lamp by a LED light with fixed power consumption. On the other hand, power consumption is a parameter used to present electrical energy converting conditions. LED components with high electrical energy converting ability can have a higher luminous flux only consuming very little power.
Luminous flux, optical spectrum is photometric data typically used to present lighting effects. Why people choose to use power consumption to present the brightness of traditional lamps instead of these more accurate photometric parameters? In the early age, when filament lamps had just been invented, the brightness of a 1-watt filament lamp is approximately equivalent to then light from one candle. Gradually, people related power consumption with brightness. Same situations happed in fluorescent lamps. Nowadays, LED lights have taken the place of traditional lights in many areas. It is improper to represent brightness though power consumption. As for LED Grow Lights, brightness of which is hard to be related with power consumption, can only be clearly represented by more scientific photometric parameters mentioned above.
As for light sources of LED lights, luminescence ability can be represented by the light distribution curve measured on their surface. Luminescence ability of the entire LED lights, the light distribution curve should be measured in front of projectors. If two lamps, no matter what type of lamps they are (super high power LED or traditional filament lamp), they will have same brightness if the light distribution curve measured before the entire lamp is similar. Brightness measured though illuminometers are usually different from brightness felt by our eyes. Under circumstances that accurate luminous flux is not necessary, brightness can be roughly represented by the measuring results from illuminometers. Since this method is cheap and easily to be realized.