pullling out sky

[Splin]

Hi there,

every now and then I bump to situation where guys have been unable to light scene uniformly. Everything on the ground is visible but sky is totally blown out. It is no biggie to bring image down few steps and all the nice cloud details start to appear in the sky. Until now in this kind of situations I have just clipped the plate values and pulled a luma key which gives good matte for the sky replacement. Sometimes foreground can cause lot of troubles if I have to deal with foliage + moving cam + strong wind.
I was wondering what other guys would be doing in that kind of situation and if there are some ways what I have not thought about yet. Since technically this is not sky replacment, sky comes from same plate and every pixel counts :p

[ShadowMaker SdR]

If you're reusing the same plate with different exposure levels I wouldn't bother using a luma key (depending on the shot of course) I'd just use the two different levels and splice them together split-screenstyle. Introducing lumakey artefacts on the original sky seems like a waste of energy. Have you got an example you can share? Maybe that will help giving you some tips.

[Splin]

I could upload .dpx if someone would like to play around with this data.
This shot is from new sony cinealta btw.

Some days ago I were wondering if tone mapping could help here. Tried few but didn't get quite there yet.

[Hugh]

Sure, chuck one up...

[Splin]

Sure, chuck one up...

Allright, I decided to put two of them up instead. They both are from same shot but are different in many aspects, other one may make someone feeling lucky :)
Or someone may feel it more challenging and would like to play around with it instead.

http://www.filmpost.ee/Tauno/FAQ/Post/0730285.dpx
http://www.filmpost.ee/Tauno/FAQ/Post/0732369.dpx

[nathan]

Heres a little messing around I did with them. I've included two results in a zip file.

One image is from a tonemap plugin I created for Nuke using the Reinhard04 method and the other is from using a compress and cc on the image.

Link for the zip file is - link (http://www.nfxplugins.com/downloads/misc/dpx_test.zip)

Heres a screenshot of the Nuke scene.

4840

[Hugh]

Splin: What software are you running?

I've got a slightly more extensive script in Shake - making sure that the sky goes down by 3.5 stops exactly

[Splin]

Oh it is you, the NFX God, I downloaded NFX plugin set but were unable to put them to good use straight away. Mot much of a shake user or colourist. Still so much to learn about grading.
Your idea to pull up darks instead is pretty clever. At first I tried something similar with Nukes histogram and clamp but it didn't work at all so well. Now as I saw Compress there I tried it again but still it did not work out. But it is cool how compress behaves!

Btw, would it be possible to add additional algorithms/presets to the tonemap? I heard there are many various ones in rendering applications.

Thanks for your play! :)

Splin: What software are you running?



I've got a slightly more extensive script in Shake - making sure that the sky goes down by 3.5 stops exactly
Nuke nowadays, used to do Fusion. Shake is out of reach, but thanks! Although it certainly would be interesting to reverse engineer it, would learn a lot.

[nathan]

N_Tonemap was nothing more than one of the first 3 plugins I created to learn Nukes SDK. Its almost a test if you wanna call it that.

It has fallen to the side as I've worked on other things. In the beginning I had hoped to have all of the psftmo tonemap filters be part of N_Tonemap. Sadly since I haven't messed with it since I created the plugin that hasn't happened.

Hopefully I will have some time to play with it again and do a full system of the psftmo tonemap filters. N_Tonemap also needs to be re-written as it contains a lot of bad code and is somewhat slow in its calculations. Only excuse I have is that it was the second plugin I ever created with Nukes SDK so my knowledge at the time was very limited.

[Splin]

nrgy, that would be ultimately cool to have.
Some results seem to be very good:
http://www.mpi-inf.mpg.de/resources/tmo/fattal02/index.html
http://www.mpi-inf.mpg.de/resources/tmo/drago03/index.html

Its a pity that there is not compiled version of pfstmo for windows available. Makes me want to get my old linux habit up and running again.

[ultrasonic]

so there have been no answers for a long time here...

does anybody know a way of tonemapping HDRs in Fusion now?

Usually i use nuke too, but the company i'm working for right now need to do that in Fusion...

thx in advance
OLi