FS7: Creating User gammas?

L

Ljung

Member
I really like how the LC709TypeA MLUT preserves a lot of dynamic range but still dials in enough contrast in the midtones to make a pleasing image. For projects where I know there's going to be little or no post color correction and I want to bake in the look, and where I want that nice latitude, I'd love to approximate that look. The biggest problem I see with just shooting in CineEI mode and baking-in LC709TypeA is that I lose the ability to nail white balance. And it's exactly those situations (baking a look because I know there won't be much CC later), where I want to nail the white balance!

I feel like a path toward achieving what I want would be to create a custom User gamma that has that same sort of curve to it, which I could then use in Custom mode and paint to my liking. Some of the HyperGammas are close, but none of them preserve as much latitude as LC709TypeA does. The camera has four slots for loading your own User gammas, but so far I've found precious little info on how to do that. Has anyone tried it? From what I've read, it seems I need to use CvpFileEditor (software I'm totally unfamiliar with) to make gammas, but then I'm a bit at a loss as to how to get them onto the camera...
 
While I am sure there are a gazillion ways to skin a cat, it takes any editor about 20 seconds to adjust the WB of a nicely exposed LC709TypeA -baked video clip in premiere, avid, fcp using the native tools or something like colorista. Especially if you've used the closest WB preset.

I think there is so much to be said for consistency and continuity of the existing known quantities when handing stuff onto other people.
 
That's what custom mode is for. Just create create your own scene file.

If you want to create your own LUT for CineEI it is easy to export one from Catalyst Browse, Da Vinci Resolve or Film Convert.
 
Ben: Yes, I know most editors can tweak the white balance with little effort. The problem is I don't always know who is going to end up with my footage, and for quick turn-around or lower budget corporate jobs, I don't always trust that the editor is going to take that small effort, or that they'll necessary tweak the way I'd want (maybe I wanted a scene a teeny bit warm, or I probably didn't want that slight green tinge, but maybe I did?)

Liam: The problem with Custom mode is that all the available gammas, even the HyperGammas, lose some latitude. And I've made my own LUTs and loaded them, but then I'm still stuck with the not-quite-perfect white balance issue. To work around this, I actually created some tweaked versions of LC706TypeA in Catalyst (slightly warmer, slightly coolor, tiny bit of minus green), but even that workaround is a bit awkward and only an approximation. All I want is to have a gamma that preserves the cameras glorious latitude, and nail white balance, at the same time!
 
Sorry to be pedantic but, latitude is the same in both custom mode and cineEI. It's dynamic range, that is reduced by a stop or two in custom mode.
 
As I said there's plenty of ways to achieve what you want but in all honesty, unless it is a feature or a commercial or something if you are not editing or colouring the piece it's not really up to you/down to you to define the end look or colours aside from either correctly balancing the WB in custom mode or in Cine-EI maybe shooting a grey card or colour chart. I always try to leave a note for the editor explaining what the footage is and what needs to happen to it if it is log or similar. If I am handing off a drive I will usually include some quick homemade colour correction LUTs on the drive.
 
Liam: Yes, I guess you're right. Should have said Dynamic Range.

Ben: Yup, agreed. If there's going to be color correction, I'm happy to pass along notes if possible, or trust the colorist, depending on the situation. But in the world of corporate video where I primarily work, I know I've done dozens if not hundreds of jobs where the footage hasn't been touched in terms of color. It looks pretty good out of the camera, and it ends up on the web or wherever in the same state. On those type of gigs, it seems like a step backwards to suddenly have to include a note with the footage that says, "I know the white balance is slightly off on most of this, can you please adjust it?"
 
Whats latitude mean then?
I've assumed they are synonyms.

I feel your pain but doubt you'll be able to get more DR out of user gammas than Sony HGs
i also sympathise with dealing w editor who is not a real colorist .

So choices :
- you can make custom LUTs , but don't count on anyone actually using them in post .
- you could shoot through filters like corals to adjust white balance in camera. (I'm experimenting with this, though you will lose exposure , perhaps sharpness , but no worse than using a protective filter .
- since slog3 is available in custom mode you could try to find a user matrix that worked , but that might be hard & won't help w a baked in LUT

thats all I've come up with .

lenny
 
I hear you, but as Liam said those exact jobs are the ones that custom mode are made for. A stop here or there won't make a lick of difference to the end result and the benefits of proper WB outweigh them.
 
Lenilenapi said:
Whats latitude mean then?
Click to expand...

In a nutshell, latitude is the amount of you can under or overexpose (pushing and pulling) in camera and still get an acceptable image in post. Dynamic range is the amount of tones from black to white a camera can capture.
 
By the way its not the mode of the camera that reduces your dynamic range (ie. custom vs CineEI) it's the gamma curve selected; slog, hypergamma, standard gamma, etc..
 
Dennis: Exactly. You can even use Slog3 as your gamma in Custom mode (kind of silly since you can't then use MLUTs, but do-able). But if you switch to one of the HyperGammas, seems like you lose about 2 stops of DR (I haven't done proper measuring, but ballpark). Since the camera has four open slots to load User gammas, I'd love to load something that retains the full DR but has a nice mid-range curve like LC709TypeA. I've started playing around with CvpFileEditor, but it's a bit awkward to say the least... Just wondering if anyone else has tried dabbling in this with any success? My goal is simply precise white balance and full dynamic range at the same time. It seems totally do-able; you'd just need to load a suitable gamma.
 
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