VFB Exposure Control - 32 Bit?

[RedStar]

Is it possible to have the exposure modifyer work on a 32bit type image? For example, here is a side by side comparison. Same light etc but left image using highlight burn to crush overexposed and then right adjusting camera fstop to darken exposure the traiditional way, as you can see there is a lot of beautiful detail in the sky however to get that I either have to do it in photoshop with a 32bit image or underexposre the whole image. Would be amazing if exposure worked as a 32bit source and was able to bring back all those juicy details with the dynamic range instead of just crushing/washing out the image?

[hermit.crab]

Everything previewed in the VFB is already 32-bit. I think you're making a mistake comparing the Highlight burn to F-stops.

From a quick test, I compared the following and I'm getting identical results:
1. VRayCamera with Physical Exposure and f-stop = 16.
2. VRayCamera with Physical Exposure, f-stop = 8 and VFB Exposure Layer's Exposure = -2

[RedStar]

Everything previewed in the VFB is already 32-bit. I think you're making a mistake comparing the Highlight burn to F-stops.

From a quick test, I compared the following and I'm getting identical results:
1. VRayCamera with Physical Exposure and f-stop = 16.
2. VRayCamera with Physical Exposure, f-stop = 8 and VFB Exposure Layer's Exposure = -2

Ah you're correct. Just did this test and same results!
Hermit do you know if you have any advice/tips/tricks on how to lets say have an image that has quite an overexposed foundation to fill in the shadows, but then take back all the overexposed areas to bring back the details to almost have like an HDR type of vibe?
I do a lot of automotive work and one issue I always run into is having the shadows just as sexy as highlights without having to do it all in post, if I can find a loophole in VFB to somehow crush highlights only so they are not overexposed that would be amazing.

Appreciate in advance!!!

[piotrus3333]

and how are you doing it in post?

[hermit.crab]

Hermit do you know if you have any advice/tips/tricks on how to lets say have an image that has quite an overexposed foundation to fill in the shadows, but then take back all the overexposed areas to bring back the details to almost have like an HDR type of vibe?
I do a lot of automotive work and one issue I always run into is having the shadows just as sexy as highlights without having to do it all in post, if I can find a loophole in VFB to somehow crush highlights only so they are not overexposed that would be amazing.

Do share what piotrus3333 asked so we can make a comparison between adjusting highlights/shadows in your post-process application and the VFB. Otherwise, you could experiment with a Filmic tonemap or a Curves layer, with which to darken the shadows and leave the highlights. Also, something to bear in mind - HDR images have different dynamic ranges (some 12 EVs, others 20+) - any post-processing (including the VFB) only manipulates the stored values. Maybe you should share the HDRI, you are using and the result, which you wish to achieve, so we can play around with it.

[RedStar]

and how are you doing it in post?

Do share what piotrus3333 asked so we can make a comparison between adjusting highlights/shadows in your post-process application and the VFB. Otherwise, you could experiment with a Filmic tonemap or a Curves layer, with which to darken the shadows and leave the highlights. Also, something to bear in mind - HDR images have different dynamic ranges (some 12 EVs, others 20+) - any post-processing (including the VFB) only manipulates the stored values. Maybe you should share the HDRI, you are using and the result, which you wish to achieve, so we can play around with it.

So the way we normally do it, once we have a base render done in 32bit, we would create variouis exposures of that 32 bit render, then convert it down to 8 or 16bit and manually brush in the details. Its just basic photoshop masking/blending but if I had a way to focus on neutralizing overexposed aras in VFB that would be epic lol.
I am lazy hahahhaa

[piotrus3333]

So the way we normally do it, once we have a base render done in 32bit, we would create variouis exposures of that 32 bit render, then convert it down to 8 or 16bit and manually brush in the details. Its just basic photoshop masking/blending but if I had a way to focus on neutralizing overexposed aras in VFB that would be epic lol.
I am lazy hahahhaa

that is indeed quite an unusual approach. blending multiple exposures of tonemapped renders would be something photographers are used to but blending not tonemapped exposures is truly unique.

if you use full highlight burn you will compress all the highlights to below 1.0 float. then you can maybe try to recover and add contrast to some parts of those highlights with some complicated curves.

what are the values of highlights you are trying to get visible details from?

[RedStar]

that is indeed quite an unusual approach. blending multiple exposures of tonemapped renders would be something photographers are used to but blending not tonemapped exposures is truly unique.

if you use full highlight burn you will compress all the highlights to below 1.0 float. then you can maybe try to recover and add contrast to some parts of those highlights with some complicated curves.

what are the values of highlights you are trying to get visible details from?

So here is a quick rough example. On the left I took the raw render .exr and made about 3 or so exposure options in 32 bit collapsing the adjustment down into each sep layer. Then Converted the full thing to 8bit and manually blended the underexposed hotspot areas. This allowed to keep the rich color of the sheetmetal while bringing back details.
On the right, I took raw render, added the exposure adjustment in vfb and took the highlight burn all the way to 0. While it brought back information it also flattened the tones and makes it look dead. All the sexy juicyness is missing.
So this is why for the moment I manually underexpose my renders in photoshop to get the beauitful range in color/tone/detail that the 32bit exrs have. If I can do this in VFB somehow it would be amazing.

[piotrus3333]

use curves for that. there is an edit point command (press enter) and you can type in values for precision.