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k4k
06-12-2004, 04:05 PM
hi.. i'm now working for a movie which vfx are to be done in DF4.... the live footages are in cineon format.. i need to add 3d elements with these footage and compose it...

could anyone help me in the conversion of cineon log to linear in DF4?

which method should i follow to match the cg elements?

Jayk2k
06-13-2004, 07:53 PM
I'm sure other's may have different ways of working with cineons, but I for one, have worked on a few projects this way now, and it has worked well for me.

Under version 4, DF now handles float color space, and will retain all the color information retained in the cineon file. Load the footage as normal, and then set the image LUT (right click on the display) and set it to a gamma of 1.7 or 1.8.

Now while working like this, just be sure to occasionally turn on the "show full color range" button in the display to make sure your highlights and shadows match the plate.

Others may argue that you should leave the cineon import as bypassed, but this can adversly effect things like color manipulation and alpha channel operations, as DF is designed to work in linear space.

Another technique would be to get the LUT's from the scanning facility and apply that on the import of the cineons. I say just let DF do all the work. ;)

Try to render your 3D as 16 bit tiff, or float if you have the drive space. This will then allow you a lot of room to color correct later. You can always render 8 bit, and then force it to float with the change depth tool, but that may contain banding coming from just 8 bits initially.

k4k
06-23-2004, 04:56 PM
hi jay... thanks fro ur reply... often i get reply from u for all of my queries!! ;) thanks again...

as for now.. i'm using this method...

1.loading the cin file...

2.adjust the softclip parameter to 89

3.and the conversion gamma to 1.7

this works well... as both highlights and shadows are retained...

Jayk2k
06-27-2004, 10:09 PM
Just be aware that there are a few caveats to this method.

1) if you are keing material from blue or green, setting the conversion gamma to 1.7 can alter the soft regions, and produce halos. You're better off leaving the conversion gamma at 1, and adjusting the display gamma.

2) By adjusting the soft clip, I believe you are limiting the conversion to a 16 bit image file (But I could be wrong on this... I can't check at the moment. )

But if it's working for you, stay with it. I find the best method of dealing with cineons is finding a workflow that you know, and can produce consistant results with.

Hugh
06-28-2004, 12:04 AM
Isn't it better to be keying in linear space as opposed to log?

k4k
06-28-2004, 06:08 PM
<JAY2K2> ya...ofcourse i'm working with cineon 16 bit footage... scanned image files are in 16 bit itself.. so as u mentioned, adjusting soft clip will bother?? if u dont mind i may send u the flow with cineon images..

<HUGH> Keying in linear rather log will affect color depth...right?

Hugh
06-28-2004, 06:21 PM
<HUGH> Keying in linear rather log will affect color depth...right?
Depends on whether you keep them at 16-bit after converting...

If you convert them to floating point before doing the log to lin conversion, you won't lose anything

Jayk2k
06-28-2004, 07:25 PM
"scanned image files are in 16 bit itself"

Cineons are a native 10 bit log file. But since most applications are based on root 2 (ie 2, 4, 8, 16) they generally represent them as a 16 bit file.

By setting a soft clip (again I believe, i've not checked this for fact yet) that you are clipping any data above where your soft clip ends. Visually in your shot now, it may not be that big a difference, but it is something to watch out for. Not only that, but you've also clipped anything below the default black level. (Or what you may have adjusted your import to).

By working in float mode, ALL the data is passed through as it appears in the cineon. Visually it may look clipped, but once it's saved back to disk it's still there. (or you can also use the show full color range on the display to view it).

Hugh: k4k is actually working in linear space with his outlined workflow, it's just that with applying a conversion gamma of 1.7, it can change the way a keyer will determine the soft regions around the subject, thus resulting in a halo.

k4k
06-29-2004, 06:10 PM
ya.. i agree u....
adjusting soft clip in my shot worked well especially in DF4, where as in MF3 i dont get...
thanks jay for ur support!! :)
thanks hugh!! :)

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