Professional lumens measurements will be made in idR with special integrating spheres, but few can afford this testing. The light in the ball on the diffuse, bright interior lining is wide spread and measured by a detector. It also measures the average reflected light and can thus determine an indication of the total amount of light.
Lumens information is unfortunately not subject to a strict standardized normalization. The lack of standardization is unfortunately exploited mainly for promotional purposes. On some websites you find items with over 6,800 lumens, which could not even theoretically achieve these lumens values even if enough voltage would be applied (see Watt’s instructions). In fact, the light output is not significantly higher than the sleeker models of other manufacturers lumen information to 900lm. Such as China lumens lumens declared information we try to counter them with more realistic valuable information, which can at least hope for a relatively accurate indication.
As an example:
Extremely bright LED flashlights offer values 1000-4500 lumens, still very bright LED flashlights offer values from 500 – 1000 lumen with small flashlights lumens values are often still perceived by 200 to be very bright.
Furthermore, it should be pointed out that quality with parts such as seals, corrosion protection, etc. which in Chinese models often do not exist and are sometimes concealed by good external appearance.