IES light

[komyali]

I have IES file, but render gets every time too dark, I need to set up vray camera to 0,0001 exposure so it gets right, but that exposure isnt realistic. Real interior exposures goes from 1-10 but this is too high... Second option is power, cranck it up 100 times more so it gets right, but that isnt realistic too because then IES emits 100 times more light than light in normal world? And this is not just with this IES file but with every IES, I read on internet, other people have problem with this too... My problem is with garage underground, I dont have any other lights in real world just neon hang from ceiling, in my big garage I have more than 1200 lights so the number isnt problem... any realistic solution to this problem?

[Corey Beaulieu]

100 times more is a lot, but I usually do have to multiply by 10 or so to get the illumination I want from an IES light. They com in set to 1250 and I may use anywhere from 7500 - 12500 in my image.

 

If you are using Vray 3, be sure that Probabilistic is turned off with that many lights. It may have been designed for such a scenario, but I don't find that it works very well. Especially not at the default of 8 lights being sampled for your 1200.

 

Lastly, Exposure is more than just an F stop. Remember that your Shutter Speed and ISO effect brightness as well and in an underground scenario I would image that these values would be pretty long/high for a real-world scenario.

 

I know this isn't really an answer to your question, but I hope it helps.

[komyali]

Just found my problem... light is done in milimeters and scene is in cm. Importind light, max does conversion and that is not good for light... also there is problems with 3ds max reading some of IES files so you need to double check IES file. Anyway thanks