Turn on ‘Preview Convert Tiles’ and turn off ‘Preview Tonemap Tiles’ in the Preview tab of the render globals. The render view will look like on a funky acid trip, but the temp file wil be alright.
I hope MasterZap will kick yer butt for calling the mia_exposure_simple pathetic. As he said, it’s called simple for a reason.
Btw, try this settings with the mia_exposure_simple: Pedestal 0.0, Gain 1.0, Knee 0.0, Compression 6.0 or higher, Gamma 2.2 (or 1.0 if you set the gamma in the primary framebuffer). This will compress the whole image into a visible range, basically the same thing you did in photoshop.
Keep in mind that burnt spots are a general problem, also in photography. If you want to have it more physiological, i.e. more working like the human eye, you wont get around local tonemappers.
easiest way to get rid of burnt areas is this: using shake to tonemap and u dont lose anything nor do u need to adjust gamma but you could do all that as well if u wanted.
i find this technique to be my bread and butter when i light with light planes(object lights)
it’s the best way i found to fix proximity problems with an idirect light source(usually an object light/plane or a visible area light) that is close to surfaces.
Thanks for the tip Floze, but I cant make it work. Disabling these options didnt make any difference in both - the open.exr files generated in the temp folder and the renderings in the Render view. I also disabled mia_exposure_simple while test rendering without these options but nothing made a difference. Can you or anyone please reproduce this with the attached scene on the first page? Is there something else that Im missing? It will be really much easier if I can use the temp files instead of batch rendering.
I hope MasterZap will kick yer butt for calling the mia_exposure_simple pathetic. As he said, it’s called simple for a reason.
He, he, LOL. No, no, I actually find mia_exposure_simple quite decent for what it suppose to do. In fact it can do all what Photoshop can do with its exposure command and may be even more as you have demonstrated with the suggested values (thank you a lot for this:thumbsup:. But bringing the image to life comes after that with color correction tools like Photoshops Curves, Levels, etc. and I meant to say that it is pathetic to try to do this with things like the Pedestal in Mia_exposure_simple which can only add some basic contrast. I didnt mean to insult the tool but to emphasize that we need additional controls, or editors, or even rewrite of Render View or imf_disp if you want to handle some basic image editing functions.
Currently it is a pain to tweak and test render by constantly using external heavy weight programs like Photoshop as feedback viewers. Even Microsoft office picture manager has brightness, contrast, saturation, midtones, etc. sliders that are very convenient when viewing photos. We just need something like that, light, convenient, and efficient that can more closely approximate and automatically update a preview of the desired result.
I have another couple of questions. This is from the Help regarding Mia_exposure_simple:
gain is the “brightness knob”. This is the main point where the high dynamic range values are converted to low dynamic range values. For example: if one knows the approximate range of color intensities goes between 0 and 10, this value should then be approximately 0.1 to get this range into the desired 0-1 range.
How can one know the approximate range of color intensity in a image? Is this in the pixels that can be measured? If so what tools, programs can do that with 32 bit files?
The other question is about the intensity values of a physical light. Is there a way to relate the number to real life measurements like watts? So far the light intensity values like the photon intensity means nothing more to me than a number that needs to be increased until my scene is lit as desired. I know that there are light profiles but can we just decide that we want a light with certain strength and translate this to an appropriate intensity value as oppose to interactive trial and error?
Emil for tonemapping in post try Artizen too! I got Very good results
with its photoreceptor & reinhard tonemappers, in the lastest version!
PS I wonder if there’s a mia_exposure_advanced in the factory? 
Ever tried to plug a color correcting node between your lens shader and the camera? The connection would look like this:
mia_exposure_simple.outValue>contrast.value, contrast.message>camera.miLensShader
Replace the ‘mi_exposure_simple’ with any lens shader and the ‘contrast’ with any shader that takes an input color, i.e. remapColor, setRange, multiply/divide, plusMinus, reverse, clamp, etc.pp. Welcome to node based thinking.
I never thought of myself as one lacking node thinking but you just proved me wrong Floze:blush:. I guess I forgot about the basics while being carried away wishing post editing features in Maya. Thank you for the great help Floze:thumbsup:, you just woke me up which is actually a reminder that I need some real sleep:).
Any ideas about recreating the curves color correction from Photoshop in Maya with nodes? I tried a few things with an animation curve node but didnt succeed.
sixbysixx, thank you for the link. It makes it clear what the possibilities are. I was already kind of aware of that. I dont expect neither am looking finding precise values that will recreate exactly a real life light intensity. My question about this came to my mind after I realized that a light intensity of 10 and then 5 million can create the same image by tone mapping. So my question put in another way is: provided it is close to impossible to recreate real life light intensity, is it then possible to tell which value is the closest to a real life light intensity from a range of different values like 10, 1000, 100 000, 1 000 000, 5 000 000, etc.?
Currently my choice would be a number that requires the least amount of tweaking for tone mapping and color correction and I wonder on what bases others make this choice.
Cpan, thank you for the suggestion, I have heard only good things about Artizen, and will try it.It’s possible with anim curves indeed, but it sort of lacks comfort. I’d use the remapHsv instead.
Cheers for all you help Floze:thumbsup:. The effect of the value graph in the RGB to HSV is similar to Photoshops curves and Im very happy with the results. I cant believe I havent paid more attention to the possibilities with these color utilities. Actually I have used most of them with great results like Contrast along with Luminance to add contrast only in the lit areas of textures, but I always thought of them as tools for fixing textures and materials. It never occurred to me that I can use them for editing the final rendered image as post effects at render time. The preview feature in the mia_exposure_simple makes this very handy and it even works nicely with the IPR. Wow I feel like discovering a whole new world of possibilities here and Im experiencing one of those happy moments that are a great boost to the love side in my love/hate relationship with Maya.:love:
Thank you and all who helped. This thread has been very helpful.This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.