POST parameter: bug or incorrect behaviour?

[cecofuli]

Hi,
the image talks for me. It seems that the changes in the Post Processing rollouct affect in some way the Corona core.
But, in my opinion, this behaviour is very odd and incorrect.
Try to think...


*(1) Ok, I like my rendering, but it's too dark.
*(2) I raise the Exposure compensation during the test rendering, in realtime. Now it's better and I like.
*(3) I want to change the resolution. I stop the render, change in.. I don't know... FULLHD
*(4) click render, but now exposition and quality is COMPLETELY different than the previous render... (O_o)
*(5) I'm shocked!

It's impossible work in this way!
Or am I wrong something?

[Ondra]

the max sample intensity parameter is relative to the current color mapping, so starting render with different exposures will result in different max sample intensity, and in turn to different amount of bias in the picture. This is so that for example MSI 10 results in the same amount of bias in dim interior shot and in bright exterior one.  But once you change exposure after the render has started, you cannot change the already rendered bias.

[cecofuli]

If I understand correctly: max sample intensity parameter is exposure dependent.
And, if yes, Exposure compensation is not very useful, because, every time I restart the render after some MSI modification in the previous test in Realtime, I'll obtain a different version, EVERY TIME! As in my attachment

In VRay I can change the Exposure in the VFB and, every time, I obtain the same image. Because the Post modifications in the VFB don't affect the sampling.
Only the Color mapping (Rehinard etc...) influence the images.

In conclusion, isn't there any solution of my problem? 

So, if I want to obtain every time the same image/quality solution, what is the correct workflow?
Do I must to start (and change :-( ) every time with the default setting:

* Exposure compensation:0.0
* Highlight compensation: 1
* Contrast: 1.0

And change their as I want? It seams to me so painful method...

[cecofuli]

No idea how to help me? =)

[Ondra]

I am still not sure what you are observing is a bug or not, but what you should do is to iterate rendering with different exposure controls to get the result you want, not reset exposure or anything like that

[cecofuli]

Keymaster, I don't know if it's a bug or now. But I want to understand how use Exposure compensation parameter.
I use it during a rendering (Render A) and I change it in realtime from, I don't know, 0 to 3, obtaining a nice render (Render B). I stop the render, i change anything (resolution, or some HD cache parameter etc... ) and I start again. The new image (Rendering C) is complete different from (Rendering B). So, how can I use correctly the Exposure compensation parameter if I don't know what happen=  In my opinion, we need a Exposure compensation parameter that doesn't affect the MSI or any other Corona core parameters, but only the final image, as Highlight and Contrast do!
Or I'm lost something? =)

[Ondra]

you can iterate, adjust exposure of render C, render over, eventually adjust exposure of render D, etc.  I could do exposure-independent MSI, but that would complicate GUI too much.

[cecofuli]

Keymaster, this is what I wanted to tell you... =) Just a exposure-independent MSI! This it would the best solution.
I know, I can Iterate (bad and not professional solution in my opinion) but as you can see in my test, with Exposure compensation: 2.5 I have not only a different "exposition", but also the quality of GI is very bad!!!

EDIT: look in third image, the ceiling and in the base of the right wall. There are a lot o splotches...  :-(

[cecofuli]

I recorder a new video. I hope this can help :)

[maru]

I think we must wait for a camera object with exposure controls. In current version it's best to change exposure in post.

[cecofuli]

maru: I think the same!

But thank. Now I understand better why Exposure compensation makes different render with the same value ;-)

[cecofuli]

Ok... loot at my next example...  How can I brighten up the image???

Keymaster, please: do exposure-independent MSI!

[maru]

it's probably because of your highlight compression @ 30

[cecofuli]

Unfortunatly no. See the image

[maru]

You are right, something is wrong here. From what I see it doesn't happen when using CoronaLights.