Chaos Corona Forum

Chaos Corona for 3ds Max => [Max] Feature Requests => [Max] Resolved Feature Requests => Topic started by: tony_morev on 2016-09-09, 17:05:48

Title: AUTO-Exposure please!
Post by: tony_morev on 2016-09-09, 17:05:48
VERY handy when it comes to complex fly through animations, when camera travels through areas of different lighting

Insight render had it :)

super simple
1) pre-render a frame at a set low res and arrive at a average exposure number, before rendering production size and quality
2) give users a multiplier to manipulate the resulting desired EV up or down
3) to prevent flickering in the animation pre-render (-2, current, +2 frames) and average the EV value out

there may be a smarter way of doing it, but that's how it was handled in Insight, and worked like a charm

thank you!

PS there's always a chance that i'm missing something, and there's already a way to accomplish autoexposure, in which case please point me in the right direction
 
Title: Re: AUTO-Exposure please!
Post by: Ondra on 2016-10-03, 16:42:35
Sorry, it does not seem to be that useful, compared to the relative complexity it would take (prerendering animation at low res), so we will not implement it
Title: Re: AUTO-Exposure please!
Post by: tony_morev on 2016-10-14, 19:14:05
may be there is a smarter way to do it? i just gave you a brute force approach

right now there is no easy way to control exposure if the camera travels through areas of drastically different lighting conditions, say between lit and unlit spaces or exterior to interior

manual animation of exposure will never look right and is a paint to set up
Title: Re: AUTO-Exposure please!
Post by: lolec on 2016-10-14, 20:50:25
There might be a way to adjust exposure dynamically for animation, the same way Timelapse triggers (who don't know the future) adjust exposure dynamically.

It's called automatic BULB RAMP, in real life photography we change the exposure time over time, and the only way to do that easily is to set the camera into BULB mode and let the trigger control the exposure time by how long in presses the shutter, anyway, that's why it's called BULB RAMP. Of course corona could much easily change the exposure.

Here is an example of a sunset simulator and how the automatic BULB RAMP feature adapts over time. http://firmware.timelapseplus.com/sunset/

This will only require to look an the previous rendered frames, and adapt future exposure slightly over time using a PID filter.
Title: Re: AUTO-Exposure please!
Post by: lolec on 2016-10-14, 20:56:33
http://www.timelapseplus.com/blog/2014/10/1/firmware-20141001-released

look at the video of the sky here to see how well this approach works.



Title: Re: AUTO-Exposure please!
Post by: tony_morev on 2016-10-14, 21:41:54
well, the real cameras have an advantage of metering before taking a shot
obviously for a rendering engine to "meter" it would have to generate a preview of a sort, even if strictly internally

that's why, i think, Ondra is dismissing it as complicated

but, the size of that preview can be very small and there is no need for AA
considering the sheer speed of corona even on heavy scenes it's a shame not to take advantage of it

even max itself has an option of auto-exposure, albeit not supported by Corona, let alone any real photo and video camera

it seems odd that developers are inclined to bring in all the complicated settings of real wold cameras letting out the convince features

ever tried shooting a non-stationary video with locked exposure? probably not, because it'll be garbage :)
Title: Re: AUTO-Exposure please!
Post by: lolec on 2016-10-14, 22:50:40
I'll be the first to admit that I'm not an expert on how Corona works, but if I'm able to change the exposure while it's rendering, shouldn't Corona be able to do the same ?

Also, if you are rendering a video, you don't want abrupt changes in exposure, so even if you transition from a dark place to a very bright one ( getting out of a tunnel ) It would be acceptable for Corona to take some time to get used to it. I don't think a 1 frame delay is a big deal, but as I said, Maybe exposure can be set just before saving.

Title: Re: AUTO-Exposure please!
Post by: tony_morev on 2016-10-18, 00:02:50
there should be a separate section for DENIED feature requests :)
cause this is hardly RESOLVED
Title: Re: AUTO-Exposure please!
Post by: JViz on 2018-05-27, 04:32:47
Sorry, it does not seem to be that useful, compared to the relative complexity it would take (prerendering animation at low res), so we will not implement it

Vray next got it now. AND auto white balance.
Title: Re: AUTO-Exposure please!
Post by: Dionysios.TS on 2018-05-27, 10:24:05
Sorry, it does not seem to be that useful, compared to the relative complexity it would take (prerendering animation at low res), so we will not implement it

Vray next got it now. AND auto white balance.

Auto White Balance and Auto Exposure are completely 2 different things. The first one is easier to do, Photoshop does it, Lightroom as well and even better. The second one is more difficult and I understand the complexity.
Personally I prefer the White Balance to be done manually in post production, much more professional move and more control.
Title: Re: AUTO-Exposure please!
Post by: Jpjapers on 2018-05-27, 16:42:43
I can totally see the need for this for animations...
Title: Re: AUTO-Exposure please!
Post by: peterguthrie on 2018-05-28, 01:17:22
one of the joys of Corona is that you can just tweak the exposure once you have started rendering, so no need to try to guess the EV level like in Vray. For animations perhaps, but normally I'd just quickly check it using interactive and then keyframe the camera exposure.
Title: Re: AUTO-Exposure please!
Post by: romullus on 2018-05-28, 10:26:22
I can totally see the need for this for animations...
I can totally see how hundreds of hours of rendering goes in to a bin, if something goes wrong with either AE or AWB or both of them :] Both features could be nice for still images, but i'm not sure if i would dare to use them on animations.
Title: Re: AUTO-Exposure please!
Post by: Jpjapers on 2018-05-28, 11:30:33
one of the joys of Corona is that you can just tweak the exposure once you have started rendering, so no need to try to guess the EV level like in Vray. For animations perhaps, but normally I'd just quickly check it using interactive and then keyframe the camera exposure.

My bad I misunderstood. I thought OP was saying that the corona camera EV wasn't keyframeable. My bad!
Title: Re: AUTO-Exposure please!
Post by: maru on 2018-05-28, 14:13:03
We have manual white balance in the vfb by the way. It's a bit hidden, but I am sure it will be properly exposed after the VFB ui overhaul in v3 (https://trello.com/b/EfPE4kPx/corona-road-map-3ds-max).
See: https://coronarenderer.freshdesk.com/support/solutions/articles/12000039650

I saw a video showing V-Ray's auto exposure, and I think it makes sense in many cases (especially in animations where the camera moves between interior and exterior). I am sure we can expect it in Corona soon as well.
Title: Re: AUTO-Exposure please!
Post by: JViz on 2018-05-29, 07:16:08
Sorry, it does not seem to be that useful, compared to the relative complexity it would take (prerendering animation at low res), so we will not implement it

Vray next got it now. AND auto white balance.

Auto White Balance and Auto Exposure are completely 2 different things. The first one is easier to do, Photoshop does it, Lightroom as well and even better. The second one is more difficult and I understand the complexity.
Personally I prefer the White Balance to be done manually in post production, much more professional move and more control.

they are indeed two different things. vray got them both.

thanks
Title: Re: AUTO-Exposure please!
Post by: JViz on 2018-05-29, 07:22:38
We have manual white balance in the vfb by the way. It's a bit hidden, but I am sure it will be properly exposed after the VFB ui overhaul in v3 (https://trello.com/b/EfPE4kPx/corona-road-map-3ds-max).
See: https://coronarenderer.freshdesk.com/support/solutions/articles/12000039650

I saw a video showing V-Ray's auto exposure, and I think it makes sense in many cases (especially in animations where the camera moves between interior and exterior). I am sure we can expect it in Corona soon as well.

is it hidden? I've always thought it was in plain sight. although "automatic" here doesn't describe it! automatic for vray means a different thing. the renderer sets the white balance with no user input besides clicking a checkbox.
Title: Re: AUTO-Exposure please!
Post by: Jpjapers on 2018-05-29, 11:17:41
We have manual white balance in the vfb by the way. It's a bit hidden, but I am sure it will be properly exposed after the VFB ui overhaul in v3 (https://trello.com/b/EfPE4kPx/corona-road-map-3ds-max).
See: https://coronarenderer.freshdesk.com/support/solutions/articles/12000039650

I saw a video showing V-Ray's auto exposure, and I think it makes sense in many cases (especially in animations where the camera moves between interior and exterior). I am sure we can expect it in Corona soon as well.

OOOH pretty!
Title: Re: AUTO-Exposure please!
Post by: maru on 2018-05-29, 11:24:36
We have manual white balance in the vfb by the way. It's a bit hidden, but I am sure it will be properly exposed after the VFB ui overhaul in v3 (https://trello.com/b/EfPE4kPx/corona-road-map-3ds-max).
See: https://coronarenderer.freshdesk.com/support/solutions/articles/12000039650

I saw a video showing V-Ray's auto exposure, and I think it makes sense in many cases (especially in animations where the camera moves between interior and exterior). I am sure we can expect it in Corona soon as well.

is it hidden? I've always thought it was in plain sight. although "automatic" here doesn't describe it! automatic for vray means a different thing. the renderer sets the white balance with no user input besides clicking a checkbox.

Quote from: maru
We have manual white balance in the vfb

;)
Title: Re: AUTO-Exposure please!
Post by: Dalton Watts on 2018-12-27, 00:27:18
+1 for this feature to be implemented in Corona! If at all possible.
Title: Re: AUTO-Exposure please!
Post by: iancamarillo on 2019-06-21, 01:15:05
has there been any further development on auto exposure? Thanks!