People find the the “lighting efficiency” of induction lamp is just “OK” but even much lower than the traditional light source like HPS or HID. Yes, that is right, however, the high lighting efficiency doesn’t mean great brightness to eyes. That’s because of the factor much invisible lights among their luminous flux. That means, though induction lighting is “not good at” lighting efficiency, it is not certain the illumination will be lower than the other light source. Please find the below tables which tells, induction lamps are quite nice for the visible spectrum. That’s the one base of difference between induction lamp and other light source. But the spectrum is not the only factor making people fuzzy on the exact brightness.
Human’s Vision is affected by many factors: light intensity, lighting distributions, different colors, objects contrast, as well fixture reflections even the motion of subjects and viewers etc.