EXR - Store Image as Tiles = No Colour Depth

[atelieryork]

Not sure if this is a bug with max, EXR or Corona, but when you save your render from the VFB out as an EXR, if you save it with Storage Type set to Tiles you will lose all your colour information and it will essentially be 8-bit. You must save it out as Scanlines Storage Type, then you'll have full 16/32-bit.

This might be an issue with default max 2016 exr output settings.

Perhaps this is a known issue?

[atelieryork]

Well...

Now for some reason I can't seem to get this to work with either scanline or tiles mode...

Something fishy is going on, and it's not just my lunch...

[atelieryork]

So if I save to EXR from the Render dialog "Save VFB" button then it strips out all Tone Mapping from the image and saves as a proper 32-bit EXR, which I can re-expose properly.

Anything I save at all from the Corona VFB manually as an EXR 32-bit float, the tone mapping is preserved but the image can't be re-exposed properly, so all the information has been clamped and lost.

I must be doing something very wrong here.

Any ideas!

[atelieryork]

Interestingly if I look at the same render in the Max Frame Buffer and save it out from there as an EXR, it also doesn't seem to work. It comes in clamped into PS.

The only way I can get an unclamped EXR out of max is by using the corona Save VFB button. But then I lose all my tone mapping...

I really must be doing something wrong here.

If I disable the CoronaCameraMod and re-render with no Tone Mapping applied, I can then save it out properly with full depth. As soon as I do any kind of Tone Mapping at all, either with Corona CameraMod or within the CoronaVFB, it clamps the image when I save it out.

[atelieryork]

Ok revelation time!

It's the "Contrast" setting in Tone Mapping - either through the mod or the vfb.

As soon as it's anything other than 1, all your depth is lost when you save the EXR out.

So there's the bug....

I should mention that I'm on Daily build from 22nd.

[atelieryork]

Now i found the actual issue, maybe the thread title could be changed, because it's not accurate at all.

[pokoy]

Could you test 2 things:

- What if Gamma Uutput is set to automatic and manual (set to 2.2)?
- Depth Format - Full Float / Half Float / Integer

Contrast works fine for me so I feel something else is causing this. For example, I have a problem with strip rendering in Backburner where one file saves black images while another one saves perfect files when merging the strips. I suspect it's something about Max and EXRs in general as there have been changes in gamma handling in 2016.

[atelieryork]

So gamma has no effect, I tested that.

And also neither does full/half/integer. They make no difference.

As far as I can tell, using Contrast for me breaks my EXR output.

[pokoy]

So gamma has no effect, I tested that.

And also neither does full/half/integer. They make no difference.

As far as I can tell, using Contrast for me breaks my EXR output.

Strange. Are you using daily builds?

[atelieryork]

Yes, from 22nd.

You?

Which version of max are you using? And which corona build?

[atelieryork]

I can confirm that this bug also happens with 1.2.1 and from within the VFB (not using cameramod). My colleague has this setup.

[pokoy]

I'm on 1.2.1, really no idea where this comes from...

[atelieryork]

I'm on 1.2.1, really no idea where this comes from...

Could you please upload a very simple scene where you're not having this issue?

And please supply the EXR with it.

[pokoy]

Oops, you're right. The file where I am using 32bits for post (and which works fine) had contrast set to 1, that's why it was working fine. I thought I was using contrast on this one.
Contrast seems to clamp values above 1.0

[atelieryork]

Oops, you're right. The file where I am using 32bits for post (and which works fine) had contrast set to 1, that's why it was working fine. I thought I was using contrast on this one.
Contrast seems to clamp values above 1.0

Cool, thought so.

I'm amazed I'm the first to spot this, apparently. Or maybe others have, but not reported it.

Maybe most people are not using Contrast for tone mapping? I started playing with it this week and really, really like how it works. You can get all the contrast and richness back into your image while having it highly exposed. Great for bright white interiors (which is what I'm working on here).

Hope this can be fixed!