Lumens and light size

[snivlem]

Hi I notice that in VRay The Complete Guide, there is this passage:

"Unlike Default, by using Lumens, the luminous flux remains the same at all times. This way one can change the sharpness of shadows by changing the size of the VRayLight"

However when I do this, it seems the light's brightness does change in value and despite it being set on lumens. Am I misreading the above quote somehow?





(Using physical camera of course)

[vlado]

The apparent brightness of the light changes, of course. It is the total amount of light emitted by the source that remains the same. If you increase the light size, then the same luminous power is distributed over a larger area, making the light dimmer.

Best regards,
Vlado

[snivlem]

Thanks for taking the time to explain that one to me Vlado, makes sense now.