The term half float linear is a bit of a strange name for a gamma curve I must say, and it definitely causes a lot of confusion. In this case, from what I understand, half float linear is a linear curve where 18% grey is mapped to 0.18. This explains why bright values are pushed above 1.0. However, I'm not full understanding what's happening. If that was the only thing that's happening compared to (the old and don't use) linear option, I would think that you could match the two with a simple multiply. But you can't. Saturation/contrast is still way different between the two.
Regarding RedCineX, in newer versions (last year or so) it allows you to export EXRs with values above 1.0. You don't have the half float linear option in there, but actually it doesn't matter what gamma setting you chose. If you render EXRs from RedCineX it will output linear EXRs with 18% grey pushed to 0.18. In my opinion the half float linear option in Nuke should be renamed to something else. Or just replace the current linear option (which is there for legacy reasons). /Simon 2011/12/20 Deke Kincaid <[email protected]> > Either way the r3d reader set to linear will clamp at 1.0, set to half > linear float will go beyond 1.0. I don't pretend to know what the red sdk > is doing under the hood. Half linear float option does not exist under > redcinex. > > -deke > > > On Tue, Dec 20, 2011 at 13:45, Randy Little <[email protected]>wrote: > >> clamped to 1.0 or raw data mapped to values between 0-1.0 with 3 >> places of precision. But I am pretty sure the d/a in every camera is >> integer and mapping data into integer space for its raw file. >> http://www.rslittle.com >> >> >> >> >> On Tue, Dec 20, 2011 at 13:37, Howard Jones <[email protected]> >> wrote: >> > 1.0 is half float/float even if not clamped ;) >> > for Ron's question (if I read it right) >> > >> > Half float or 16 bit float is a less accurate version of 32 bit float. >> > AFAIK The float being the floating point part of the number. you dont >> save >> > 123.45678 you save 12345678 with a bit(?) for the position of the >> floating >> > point. >> > The difference between 16bit (half float) and 32 bit (float) is that >> with >> > 16bit the length of that number gets truncated at a lesser degree of >> > accuracy compared to 32bit. >> > You could have 10 or 8bit float if you wanted, just not much point for >> what >> > we do. Similarly you could have 32bit non-float if you really wanted, >> but >> > again no point in our game afaic - as far as I care ;) >> > >> > Linear is linear, but again you could put any gamma or other curve in >> there >> > if you wanted. >> > >> > http://en.wikipedia.org/wiki/Half-precision_floating-point_format >> > >> > Howard >> > >> > ________________________________ >> > From: "[email protected]" <[email protected]> >> > >> > To: Nuke user discussion <[email protected]> >> > Sent: Tuesday, 20 December 2011, 20:24 >> > Subject: Re: [Nuke-users] Redcine-X VS Nuke >> > >> > 1.0 is half float if it encoded half float and clamp to 1.0 >> > >> > Sent from myTouch 4G >> > >> > ----- Reply message ----- >> > From: "Deke Kincaid" <[email protected]> >> > To: "Nuke user discussion" <[email protected]> >> > Subject: [Nuke-users] Redcine-X VS Nuke >> > Date: Tue, Dec 20, 2011 12:13 >> > >> > >> > Last I knew RedcineX only outputs EXR to "linear" which caps out at >> 1.0, not >> > half linear float. >> > >> > -deke >> > >> > On Tue, Dec 20, 2011 at 04:29, Simon Björk <[email protected]> >> wrote: >> > >> > I might be misunderstanding you, but why the srgb2lin conversion? >> RedcineX >> > only outputs linear exrs so as far as I know you shouldn't use any >> > colorspace convertions in Nuke if you chose that path. You can test >> this if >> > you try different gamma curves in RedcineX and render to EXR. They >> should >> > all look identical. >> > >> > Regarding my earlier post about half float linear gamma setting in Nuke >> > should match a rendered exr from RedcineX, I just tested this and it >> doesn't >> > seem to work. I'm pretty sure this worked earlier, but I might be >> wrong. The >> > "linear gamma curve" in Nukes R3D importer is an old one and shouldn't >> be >> > used. Not sure why it's still there. >> > >> > This whole R3D in other applications often causes problems. Same in >> After >> > Effects. I find that the most reliable solution (still unreliable) is to >> > output from RedcineX. >> > >> > /Simon >> > >> > >> > >> > 2011/12/20 Deke Kincaid <[email protected]> >> > >> > I forgot to mention that It all depends what file format your >> outputting. If >> > your outputting to dpx or tiff then set the decode colorspace/gamma >> curve >> > the same as RedcineX but in the write node set the colorspace to >> "linear". >> > While working with the R3d though, the viewer will look different from >> > RedcineX unless you set it to linear. After reading back in the >> dpx/tiff, >> > then you can set the viewer back to srgb and it will look correct. >> > >> > If your outputting to Exr from RedcineX then you need add a colorspace >> node >> > with in:sRGB and out:Linear (Read node settings all should match >> RedcineX). >> > While this is technically incorrect but it will give you the >> equivalent of >> > burning the grade into the EXR. >> > >> > People here are mentioning using Half Linear Float which does properly >> > linearize the curve form the chip when going to EXR. You would need to >> > extract a lut between the linear R3d and your director's color to use >> as a >> > viewer lut and use that in the write node. >> > >> > -deke >> > >> > >> > On Tue, Dec 20, 2011 at 00:15, Ron Ganbar <[email protected]> wrote: >> > >> > Thanks for this Deke. >> > The settings are all the same, but looking at the Nuke Viewer set to >> sRGB, I >> > see a very washed out image - what I would normally consider a Cineon >> > looking image. Looking at the Redcine-X viewer it looks correct. >> > Any ideas? >> > >> > >> > Ron Ganbar >> > email: [email protected] >> > tel: +44 (0)7968 007 309 [UK] >> > +972 (0)54 255 9765 [Israel] >> > url: http://ronganbar.wordpress.com/ >> > >> > >> > >> > On 20 December 2011 09:48, Deke Kincaid <[email protected]> wrote: >> > >> > First, try hitting the "Metadata" button in the read node. That should >> make >> > it grab the right color settings. If not you can match the same >> settings in >> > Nuke as the one he has in RedcineX (they should all be named the same). >> > >> > Also make sure your using Nuke 6.3v5 because it includes RedGamma2 and >> > RedColor2 which is missing from versions before that (older SDK). >> > >> > -deke >> > >> > On Mon, Dec 19, 2011 at 23:34, Ron Ganbar <[email protected]> wrote: >> > >> > Hi all, >> > I don't have a lot of experience with converting R3D files, but I so >> far did >> > it with Nuke and was pretty happy with the result. >> > However, a director, who is technically minded, just told me that when >> he >> > takes something into Redcine-X and without changing the color at all he >> gets >> > something he likes. I did the same thing, and indeed the image looks >> nice. >> > When I do the same thing in Nuke I get a very washed image. What's the >> > output colorspace of the Nuke R3D read node? How can I get the same >> kind of >> > output from Nuke's Read node to Redcine-X's output? >> > >> > Thanks, >> > Ron Ganbar >> > email: [email protected] >> > tel: +44 (0)7968 007 309 [UK] >> > +972 (0)54 255 9765 [Israel] >> > url: http://ronganbar.wordpress.com/ >> > >> > >> > _______________________________________________ >> > Nuke-users mailing list >> > [email protected], http://forums.thefoundry.co.uk/ >> > http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users >> > >> > >> > >> > _______________________________________________ >> > Nuke-users mailing list >> > [email protected], http://forums.thefoundry.co.uk/ >> > http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users >> > >> > >> > >> > _______________________________________________ >> > Nuke-users mailing list >> > [email protected], http://forums.thefoundry.co.uk/ >> > http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users >> > >> > >> > >> > _______________________________________________ >> > Nuke-users mailing list >> > [email protected], http://forums.thefoundry.co.uk/ >> > http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users >> > >> > >> > >> > >> > -- >> > -------------------------------- >> > Stiller Studios >> > Lidingö/Sweden >> > >> > Simon Björk >> > Stiller Studios >> > +46 (0)8 555 23 560 >> > Ekholmsnäsvägen 40, S-181 41 Lidingö >> > [email protected] >> > www.stillerstudios.se >> > >> > find us: >> > >> http://www.eniro.se/query?search_word=stiller+studios&geo_area=liding%F6&what=all >> > >> > >> > >> > _______________________________________________ >> > Nuke-users mailing list >> > [email protected], http://forums.thefoundry.co.uk/ >> > http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users >> > >> > >> > >> > _______________________________________________ >> > Nuke-users mailing list >> > [email protected], http://forums.thefoundry.co.uk/ >> > http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users >> > >> > >> > _______________________________________________ >> > Nuke-users mailing list >> > [email protected], http://forums.thefoundry.co.uk/ >> > http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users >> _______________________________________________ >> Nuke-users mailing list >> [email protected], http://forums.thefoundry.co.uk/ >> http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users >> > > > _______________________________________________ > Nuke-users mailing list > [email protected], http://forums.thefoundry.co.uk/ > http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users > -- -------------------------------- Stiller Studios Lidingö/Sweden Simon Björk Stiller Studios +46 (0)8 555 23 560 Ekholmsnäsvägen 40, S-181 41 Lidingö [email protected] www.stillerstudios.se find us: http://www.eniro.se/query?search_word=stiller+studios&geo_area=liding%F6&what=all
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