Auto exposure to keyframes?

[YoyoBoy]

Would there happen to be any way to write Auto Exposure values to keyframes on the camera? Sometimes it gets a little jittery when rendering on a farm, so it would be nice to set it in stone and be able to make edits.

[^Lele^]

You can surely do it with autokey, and exposing + transferring it to cameras at different keyframes.

[YoyoBoy]

Where can I find the exposure values that Auto Exposure decides on?

[^Lele^]

It modifies ISO, so to not change moblur or DoF.

[YoyoBoy]

Huh? Auto Exposure isn't tweaking the ISO setting on the camera itself. It's happening to the render. And I don't see any mention of what it's doing in the Log...

[^Lele^]

Exposure at rendertime is a multiplier on the whole image values.
That multiplier is then used when the transfer button is clicked to modify the camera ISO accordingly.
The ISO are what is going to get keyframed.
From the variation in ISO you can find out what the multiplier was.

[YoyoBoy]

But how can I find out what this new ISO number is???? Where does this information appear?

[^Lele^]

It's on the camera properties panel, for physical cameras only, of course.

[YoyoBoy]

Um, no it doesn't.
Step 1) Render a scene with an inappropriate ISO number
Step 2) Feel sad that your render didn't come out right.
Step 3) Turn on Auto Exposure in the camera panel in the VRay tab and render.
Step 4) Feel happy that your render came out nice
Step 5) Wonder what ISO number the Auto Exposure found that worked so well for your scene, because it did not change that setting on your camera.
Step 6) Wish there was a way to make Auto Exposure set keyframes on the camera's ISO, because your shot is two minutes long and goes from outside to inside, past courtyards, and a variety of other drastically-lit situations, and there's a fountain that has occasional sun reflections that cause Auto Exposure to close the ISO way down for just one or two frames here and there.

[^Lele^]

Um, no it doesn't.
Step 1) Render a scene with an inappropriate ISO number
Step 2) Feel sad that your render didn't come out right.
Step 3) Turn on Auto Exposure in the camera panel in the VRay tab and render.
Step 4) Feel happy that your render came out nice

Here is where you need to transfer exposure to the camera(s)

Step 5) Wonder what ISO number the Auto Exposure found that worked so well for your scene, because it did not change that setting on your camera.
Step 6) Wish there was a way to make Auto Exposure set keyframes on the camera's ISO, because your shot is two minutes long and goes from outside to inside, past courtyards, and a variety of other drastically-lit situations, and there's a fountain that has occasional sun reflections that cause Auto Exposure to close the ISO way down for just one or two frames here and there.

[YoyoBoy]

You still aren't telling me where to get that ISO number. It does not apply it to the camera.

[YoyoBoy]

Or does it not work on VRay camereas?

[seandunderdale]

Are you rendering on GPU?

[YoyoBoy]

Nope. CPU. And just now I checked VRay Exposure Control vs. Physical Camera Exposure Control, and neither changes the settings on the camera.

[seandunderdale]

I found the ISO number copied over to my camera. Maybe Im missing something, but if I have iso 100 in my physical cam, then turn on auto exposure, hit render, then transfer settings to camera, my iso changes to 300ish in the scene I tested. Is that whjat youre trying to do? I assume I could then do various auto expsure renders in a walk through and get the ISO number for that frame, and keyframe it.