EV at 0.

[DanSHP]

Recently I've been setting my camera to 0 EV and instead just increasing/decreasing the output of my HDRI lighting map to render. This to me, is more streamlined as I do not have to change camera settings when I switch HDRI's (I just have to amend the HDRI multiplier).

In order to get the correct amount of light into my scenes via the HDRI I simply place an 18% grey card into my view, and adjust the HDRI multiplier until the grey card is around 0.459 (18% grey) when I sample the plane in the VFB. Just like how a camera meters off a grey card.

This is working great so far. Having a full understanding of PBR material workflow and combining the use of scans, everything just works nicely together.

Yet I'm going to assume there are a few pros and cons to this approach? Right?

[glorybound]

I try to work using V-Ray Sun/Sky/Camera, exposing everything properly and then replace my Sun/Sky with an HDRI and I increase/decrease my HDRI multiplier to work. Almost every HDRI is different, but at least I have a solid base with V-Ray Sun/Sky/Camera. I'll have to try your gray card process.

[DanSHP]

I try to work using V-Ray Sun/Sky/Camera, exposing everything properly and then replace my Sun/Sky with an HDRI and I increase/decrease my HDRI multiplier to work. Almost every HDRI is different, but at least I have a solid base with V-Ray Sun/Sky/Camera. I'll have to try your gray card process.

Yes, I've heard of that approach.

I'm wondering what the difference is though? I know the vray sun is physically correct a HDRI not, but if I can achieve the same 0.459 grey card with both the sun and HDRI - to me at least it shouldn't make a difference which one I use. Also, using vray sun and then switching to a HDRI is a bit jarring in terms of judging look and feel. It's pretty unlikely you'll ever match HDRI sun position to a vraysun, again making it difficult to judge how things will look when you switch (lighting/shadows etc.) As a consequence using vraysun to set exposure then switching to a HDRI instead voids any camera settings you set up with vraysun. Right?

[glorybound]

Yeah, I am not saying my way is superior. I Keep the V-Ray sun and I just align it to my HDRI's sun. I was using a 30 multiplier for one HDRI that I use and I exposed the camera to work, but I knew those numbers were not accurate, which messed up all my interior light settings. I reworked my workflow, got everything working with all V-Ray stuff (Lights, Cameras, Sun/Sky), and then swapped out to an HDRI in the V-Ray Dome. The multiplier went to 100 and I kept all my accurate camera settings; it worked perfectly. Now, I can use real-world camera settings and light lumen settings.

[DanSHP]

Yeah, I am not saying my way is superior. I Keep the V-Ray sun and I just align it to my HDRI's sun. I was using a 30 multiplier for one HDRI that I use and I exposed the camera to work, but I knew those numbers were not accurate, which messed up all my interior light settings. I reworked my workflow, got everything working with all V-Ray stuff (Lights, Cameras, Sun/Sky), and then swapped out to an HDRI in the V-Ray Dome. The multiplier went to 100 and I kept all my accurate camera settings; it worked perfectly. Now, I can use real-world camera settings and light lumen settings.

I did wonder how real world interior lighting units would work under a zero EV camera. I don't do many interiors, but in my mind as long as you're in the 18% grey card area, it should work just fine.

[DanSHP]

Also, using EV you can use motion blur and DOF independent of ISO and shutter speed. Haven't had chance to test yet, but I'm guessing EV at 0 it should work the same.

[francomanko]

Why 18% grey?

[DanSHP]

https://corona-renderer.com/forum/in...8138#msg138138

[piotrus3333]

more streamlined? sounds like more mess. just save your environment maps to your library as VRayHDRIs with correct output multiplier.

[DanSHP]

more streamlined? sounds like more mess. just save your environment maps to your library as VRayHDRIs with correct output multiplier.

I've always avoided doing this, as the 3ds max material browser takes its time loading in mats as it is. HDRI's I assume would take even longer. Anyway thoughts on how to speed this up?

Also the 0EV approach above (with 18% grey card), does this seem like a sensible idea? It just seems to me at least, I only have one value to adjust (the HDRI multiplier) I do not have to mess around with camera settings too (ala streamlined).

[piotrus3333]

what do you do with many cameras within the scene that need different exposure?

how do you set up intensities of artificial lights to match your environments?

raw render besides good exposure needs contrast adjustment as well so add black and white too. ( I use 10 and 204 RGB).
like here (black sphere behind the model):

[Ihno]

Anyway thoughts on how to speed this up?

convert them to tiled exrs they load in no time.

[DanSHP]

what do you do with many cameras within the scene that need different exposure?

how do you set up intensities of artificial lights to match your environments?

raw render besides good exposure needs contrast adjustment as well so add black and white too. ( I use 10 and 204 RGB).
like here (black sphere behind the model):

I have calibrated my HDRI's to vray sun. So, my HDRI's should be more or less physically accurate, therefore any artificial lights should work as it would with the vray sun.

[DanSHP]

convert them to tiled exrs they load in no time.

Top tip!

Cheers

[Vizioen]

I have calibrated my HDRI's to vray sun. So, my HDRI's should be more or less physically accurate, therefore any artificial lights should work as it would with the vray sun.

How did you calibrate them?