IES light power setting

[diogodasilva@mac.com]

Re: IES light power setting

I feel nomatter which ies file u use, the light power is always underrated. For example in real life, in the scene u set up would've been overexposed with an iso that high. And on vray it barely scratches... So you find yourself always having to compensate. Either camera or the light power setting.

Also, very often people use IES files for spot lamps, mr16, par, ar, ... The power of these is measured in candelas, not lumens.

Im not sure what is going on there then, I found it to be the complete opposite to what you describe. My IES lighting is too intense for my scenes and needs toning down...

it I leave the IES light power on zero as advised, I have to use extreme settings on the camera in order to see the light, for example: F stop 2, ISO 3200... making it impossible to use sun and ies lights at the same time in some scenes..

I will post some images...

[diogodasilva@mac.com]

Re: IES light power setting

Link for the image:

http://img193.imageshack.us/img193/8307/capturehul.png

as you can see, the IES file is from a fairly powerful lamp (from GE) and this camera settings does not represent a real world result.. as if the engine is not tuned for real life physics ... I am no programmer, but as a lighting designer I should know one thing or two about lights. I don't know... maybe its is my settings or something I haven't figured out yet!

Thanks in advance for everyone replying!

Cheers...

[edonk]

Re: IES light power setting

Which version of vray is this you are using?

[diogodasilva@mac.com]

Re: IES light power setting

Installed version is 01.48.83

But on the render stamp it says Vray Core 1.70.00

[edonk]

Re: IES light power setting

I'm not sure why you are getting these results. Let me know which IES file you are using so I can test the same and show you the result. I get mine from GE website.

[diogodasilva@mac.com]

Re: IES light power setting

I'm not sure why you are getting these results. Let me know which IES file you are using so I can test the same and show you the result. I get mine from GE website.

another scene:

http://img59.imageshack.us/img59/563/capturehdp.jpg

Files used from GE:

C:/Users/Diogo Moreira/Desktop/My Dropbox/SV/IES DATA/GE/35AR111-FL24_(97533).ies
C:/Users/Diogo Moreira/Desktop/My Dropbox/SV/IES DATA/GE/100PAR-H-SP10_(17992).ies
C:/Users/Diogo Moreira/Desktop/My Dropbox/SV/IES DATA/GE/Q71MR16-C-CG40_(20873).ies
C:/Users/Diogo Moreira/Desktop/My Dropbox/SV/IES DATA/GE/Q50MR16-C-CG15_(20872).ies
C:/Users/Diogo Moreira/Desktop/My Dropbox/SV/IES DATA/GE/45PAR30-HIR-SP9-XL_(41545).ies

[edonk]

Re: IES light power setting

Are you happy with the render output there? It looks ok to me.

[diogodasilva@mac.com]

Re: IES light power setting

don´t you think this camera settings are WAYY too extreme?

What I mean is:

On a real world scene, and with a real world camera this image should have been fully blown overexposed ...

Come on.. a full second of shutter release... F stop 2 ... and 3200 ISO ... this image should be all white!

[dkendig]

Re: IES light power setting

does it work like this in Max? We didn't write the IES light code at all, that's all Chaos Group. If the light works the same as it does in Max, then there is no bug. If the light works differently, then if we can figure out what we need to adjust to make it work properly we will. There was an issue in the past where IES lights were entirely too dark, but that was due to a units issue. We fixed that issue, and now they should be working the same way they do in V-Ray for 3D Studio Max. We were told that the light was functioning as it does in Max, but if anyone would like to point out any differences between the way the two lights function, I would be willing to see if there's anything that we can do about it.

[diogodasilva@mac.com]

Re: IES light power setting

I have no experience with max so I can't comment on that...

I guess we can't expect to "have it all at once"... trial and error will continue to do its job...

[fpedrogo]

Re: IES light power setting

As I said before the physical camera reduce the exposure of the IES lights and the IES light power is in lumen. A typical 100W electric bulb emits about 1500 lumens of light. So if you use the physical camera you have to use a very very very high IES light power. If you don't use the Physical Camera, then it is what Devin said, with the default IES power data sould be enough.
When I said that you have to use the physical camera to control the exposure of the scene. I was not referring that you control the brighter of the lights (multiplier or power) with the camera, so the value that you use for the camera are crazy values . You should use the Physical Camera to control the exposure of the sun and the lights multiplier or in the case of IES, the power, to control the exposure of the lights. Again the Physical Camera reduce the brightness of all the lights type even IES lights. This is the way how work in Max too.

Best