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render saving - exr confusion

Posted: Wed Feb 22, 2012 11:48 am
by Rogurt
Hi all

I save a render as png, exr, exr tonemapped.
The tonemapped exr seems to be flattened in dynamic like an LDR. The PSD tonemapping dialogue shows just 6 EVs used. With the exr saved without tonemapping the picture uses 15 EVs. This exr seems not to have the exposure setting I defined in Octane represented in the exr displayed in PSD. When I turn up the PSD viewing exposure (of live display) the luminance resembles the png but the colors are visibly different like if the camera response curve was not taken into account for the saved exr.

Can someone give me some advice on this? I would like to have a full dynamic exr with colors of the camera response to tonemap in PSD...

Cheers,
Rogurt

P.S. V2.57 seems to have full 32bit in exr, no? PSD tonemapping dialogue shows 15 EVs used in the picture (the untonemapped version). I ask because of it´s been said that only 16bit are saved in exr here http://www.refractivesoftware.com/forum ... f=9&t=2924

Re: render saving - exr confusion

Posted: Wed Feb 22, 2012 9:21 pm
by roeland
EXR without tonemapping is exactly that, no tone mapping. So the exposure, film curve and other imager settings are not applied.

Saving as tonemapped EXR will not retain the highlights in the scene, hence the loss of dynamic range. This is a limitation of the film curves used. You can't have both the full dynamic range and the film curves.

EXR is saved as 16-bit floating point values, which can encode much more than 16EV of dynamic range (up to 40EV in theory).

--
Roeland

Re: render saving - exr confusion

Posted: Thu Feb 23, 2012 12:17 pm
by Rogurt
thanks for the explanation. a pity one cannot have both response curve and high dynamic range...