Please help! my light in iray render is low no matter how much i change intesity

toblin99_d15f4098e0

Can anyone help me please? I spent whole day playing with distant lights and spotlights but no matter how much I change the intesity the light is low like this. I tried to render it with camera and setting headlamp off but no effect, still the same intesity

Richard Haseltine

Set the intensity back to 100% and try adjusting the luminance settings in the Photometrics group. Also try rasising the Exposure value in the Tone Mapping group of Render Settings.

toblin99_d15f4098e0

I allready tried setting luminous higher to over 5000 no effect. I tried raising exposure value in tone mapping to 60 it's even darker. I don't understand why is this happening

Richard Haseltine

Ah, exposure value is odd  -actually lower it (the things that influence its value are cnsistent in their effect - I usually adjust the Shuter speed, ISO and fStop values directly. As I said, don't try to use Intensity, use the Luminance values.

toblin99_d15f4098e0

I raised film ISO a lot and it's much brighter now. I still want to figure out why this happenes though

toblin99_d15f4098e0

and thanks Richard for replying mate!

prixat

It could be because you are using a Distant Light. That Lumens value is spread over a huge area.

I would try 40,000 or 50,000 on a distant light. 5000 on a nearby spotlight. 1500 is good for a bulb in a lamp.

 

SpottedKitty

toblin99_d15f4098e0 said:

I still want to figure out why this happenes though

It's happening because Intensity is a 3Delight function of the light. The Photometrics functions below that are for Iray. You can't mix the two, you have to use the Lumen and Temperature values in Iray, because that's how real lights work in the real world.

Tobor

Looks like you're making too many changes in opposite directions and getting yourself tripped up.

1.Return to normal tone mapping. A value of EV 60 is WAAAAAY too low. You're hardly letting any light into the Iray camera at all.

2. For distant lights, leave Intensity at 100%, and change Lumimnous Flux to about 10. That's right, 10. Distant Light values are calculated as light *incident* on the scene, not light produced by the source. A distant light is assumed to be an infinitely distant source where all the rays are parallel. Therefore, there is no fall off or spread of the light, as there is with the other D|S light sources. 

A value of 10 is approximately equivalent to light from the sun at noon. The 10 means 10 lumens per centimeter square incident on the scene, which is actually a ton of light.

Be aware that the physical location of the distant light in the scene doesn't matter, only its direction. You can set the direction into the scene by selecting your distant light in the View, and adjusting the controls to rotate and move it up and down. You can't render though the infinite light view, so be sure to switch back to your camera first.

If you're still experiencing od effects, try quitting  D|S, restarting, and reloading your scene from scratch.