Chaos Corona Forum

Chaos Corona for 3ds Max => [Max] I need help! => Topic started by: Ink Visual on 2018-03-20, 16:27:44

Title: Default simple exposure
Post by: Ink Visual on 2018-03-20, 16:27:44

Hi there,

I'm using Corona for quite a while now, but today I got a bit confused.
For all that time I have been using photographic settings to set up my lighting. By doing that I was able to qickly get physically correct setup.  After reading couple of posts on the forum I came into conclusion that using simple exposure might actually be better, more flexible solution. Although...

With a default Corona Sun (intensity: 1) I get my images super overexposed. I usually have to set the simple exposure to something like: -5, -4 to get it all right...
Why is that? Shouldn't the default EV-0 value be giving me the neutral, more or less properly exposed images?

Is it just me? Some wrong scene settings? Or maybe all of you, while using simple EV settings, usually have them around -4, -5?

Thanks,
Michal

Title: Re: Default simple exposure
Post by: NicolasC on 2018-03-20, 16:42:01

Hello,

Same confusion here ... despite the global ease of use of Corona, that's an area where I'm not comfortable at all. EV-0 doesn't have a sense if one is based on such EV table. Definitely something I don't understand neither.

Title: Re: Default simple exposure
Post by: NicolasC on 2018-03-20, 16:48:44

Found this thread:https://forum.corona-renderer.com/index.php?topic=17910.0 (https://forum.corona-renderer.com/index.php?topic=17910.0)
Might help a bit ... or not :)

Title: Re: Default simple exposure
Post by: Ink Visual on 2018-03-20, 17:23:23

Thanks a lot Nicolas.
So it makes it a bit more clear now, according to what Juraj wrote:

"But it works like this: You put simple white color into environment (255/255/255), create some object ( Teapot with 128/128/128 Grey color ), hit render, and the teapot at EV=0 will be exactly 128/128/128."

And that seems to be correct. When I use white background in environment with EV=0 it does work as expected (see attachment).

But then while using corona sun in environment slot, I have to lower EV drastically (-4, -5) cos otherwise it's all just white (see 2nd attachment).
From what I understand now, all of you have to adjust EV the same way then?

Thanks!

Title: Re: Default simple exposure
Post by: romullus on 2018-03-20, 17:33:13

Yes, that's correct, direct sunlight at noon, requires EV adjustment of about -4 -5 to be exposed properly.

Title: Re: Default simple exposure
Post by: Ink Visual on 2018-03-20, 17:45:37

Great, thanks a lot for clarification.