watts II

[ene.xis]

hi to everyone!
i m spending this last days messing with RC2 after some relaxing holydays and benn delighted with all the new stuff in this build! it s really an excellent product!i m most proud of my beloved Vray capabilities!
Congratulations Chaos team!

now i m having some doubts with few things mostly about units...
i ve got this scene i ve been messing with and i f i use 40 watts vraylights the light intensity is so high that i ve got to reduce so much the vrayphycam exposure that the sun+sky outside (remaining with the intesity at 1) becomes completely dark...however if i reduce the 40watts vray lights to 0,4watts its close to wat i would expect....?should i change my working units?


F stop: 5.6
shutter speed: 40
ISO: 400


F stop: 5.6
shutter speed: 3100
ISO: 400

any help apreciated!
thanx in advance

[dlparisi]

The 40w bulbs don't produce 40w of visible light, which is what the vray value is refering to. The 40w bulb probably produces around 1-2 watts of visible light so your number of 4w may even be high (unless its halogen or fluor.). Refer to http://en.wikipedia.org/wiki/Incandescent_bulb for some more info.

David

[ene.xis]

i m quite aware of that but the value i got to was 0,4 wich i reckon is too low.
So i guess it must not be that...?

[dlparisi]

Sorry, I missed the 0,4 in my quick read. Maybe an easier way to do this is to enter the lumens produced by a 40w bulb. According to Osram Sylvania their 40w a-lamp produces 460 lumens. Enter this in the units for Luminous Power (lumnes) and change the Unit type to Radiant Power (Watts) and it will change the value to .67. Not that far from .4.

David

[ene.xis]

humm...well i see...u r right
"insert thumbs up smiley here"



still i d thought there could be a scale/units problem rather than a value error, or else its rather useless to use the watts input in the vraylight intensity...i wonder...?

[vlado]

still i d thought there could be a scale/units problem rather than a value error, or else its rather useless to use the watts input in the vraylight intensity...i wonder...?

Usually you'd use lumens for this, and not watts.

Best regards,
Vlado

[ene.xis]

i see.
thanx vlado and dlparisi!
most apretiated