FS7: Warming filter for FS7

M

meauounji

Well-known member
Hi guys,

So, I've shot two jobs with the FS7 now, both in Cine-EI, one with burned in LC709A, one without, and I'm noticing that the camera tends to run cool in color temperature, at least it runs cool for my preference.

I'd like to add a warming filter to the front of the lens, something that simulates about a +500 Kelvin or so in white balance. I don't know much about filters available for use in a matte box beyond ND's and polarizers. Any veteran shooters out there have some advice on what to use? In fact, I'd wouldn't even mind a +1000k filter for use on overcast days.

To those of you thinking "Just do it in post" I do enough jobs where I have any involvement in post, so I'd really rather do it in camera.

Thanks, all.
 
I've noticed the same thing and was thinking about digging out some old warming filters. A Wratten 81A would be a good place start.
 
The best filters for this traditionally are Corals (basically the same as CTO) because they have a very clear system 1/8 thru 9 or so where C2 or 3 is approximately a Full CTO . I always used to carry 1/8 and 1/4. The other system for naming warming filters was Kodak's - which would start with an 81A, 81B , 81C etc .

http://cinematography.net/edited-pages/MiredShiftForCoralFilters.htm

You can find these all described on B&H under Light balancing/Color conversion filters. Also you can search for coral filters . A nice filter that also adds a touch of magenta is Tiffen's 812 but i haven't tried one in years.
 
Can you not build a 'Scene File' (s)

709-5500k-warm ? etc

Im not personally a fan of extra glass in the image path.

S
 
You can just warm up your WB in the menu.
NO need for filters...

Paint menu
>Offset White
>Warm Cool (balances blue-yellow)
> Warm Cool Balance (balances green-magenta)

Dial it in and your manual WB will be warmed up.
 
If you are using EI surely you would just build a warmer LUT.

Being properly nerdy it is important to keep all channels in the fat zone of the file so a filter may not help or may (did Red users find blue on the lens under tungsten lead to cleaner files?)

S
 
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Erik Wittbusch said:
If somebody wants a "Scene file" he does obviously not use cineEI...
Click to expand...

This thread has nothing to do with custom mode Erik. Pay attention:-)

@Morgan if you don't like glass in the image path, why use a lens? J/k Seriously, the idea with EI mode is to treat it like a film camera. If I was shooting on 5600 kelvin film stock but I was shooting in 5000 light I'd slap on a filter. It's got to be worth a test at least...
 
Front filters do degrade the image cause bouncing light issues etc - good ones properly matted less so of course.. and bad ones poorly matted could bring an aesthetic of flares and the like. (flares are a thing I like and cannot be done in post IMO)

The one thing about film cameras is you can choose a stock and how it is cooked to create a look - maybe kodak and fuiji have different looks for example - IMO the digital equivalent of choosing a stock would be use of luts/looks/post in general.

The OP posed the thread in a feel of getting technical correction as opposed to creating art looks, id be surprised if you cannot get a higher level of technical correction by not using a physical filter.

IMO anyone looking for technical accuracy should be shooting a gregtag card and then matching it using the appropriate facility in the Resolve (or speedgrade) suites. In my colour critical stills catalogue work that is what we have done for a decade. In one click we get a correct image that accounts for colour temp, lights, different cameras, everything!

S
 
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No one is suggesting using a poor filter. Using an optical filter before all the image processing makes a lot of sense. So much so I'll test it this afternoon.
 
The OP could also consider a warm card - click balancing off a slightly blue 'white card' - or maybe just click balancing.

This will work for the 709 jobs and might work if Custom Slog is a doable workflow.

It wont work for EI of course.

Use of a deep blue filter under tungsten is a worthy consideration as it forces one to use more light and stress the blue channel of the chip less.

--
IMO shooting CineEI is for when one knows the footy will get treatment in post and on that basis a small %* kelvin shift on location should not present issues.
Custom Slog should be used for a 'one click' post workflow (addition of a single LUT)
709 should be used for 'no click' post workflow
CustomSlog has no LUTs of course, take a choice there or consider an externally lutted monitor.

S


* % might not be the right phrase as kelvin is a non linear function
 
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A lot of the greatest films ever made were shot through coral filters, let alone heaps of diffusion, so I wouldn't be too afraid of them either.

Liam,
Have you found that recording to 709TypeA LUT is a better look than the hypergammas?
I am intrigued by this question but haven't had time to check yet.

I am also considering carrying filters when needed. It is true though that creating your own LUT's is probably the best option. Haven't reached that level yet though.
 
Lenilenapi said:
The best filters for this traditionally are Corals (basically the same as CTO) because they have a very clear system 1/8 thru 9 or so where C2 or 3 is approximately a Full CTO . I always used to carry 1/8 and 1/4. The other system for naming warming filters was Kodak's - which would start with an 81A, 81B , 81C etc .

http://cinematography.net/edited-pages/MiredShiftForCoralFilters.htm

You can find these all described on B&H under Light balancing/Color conversion filters. Also you can search for coral filters . A nice filter that also adds a touch of magenta is Tiffen's 812 but i haven't tried one in years.
Click to expand...

Thanks Leonard for the clear summary. Extremely useful information.
 
Lenilenapi said:
Liam,
Have you found that recording to 709TypeA LUT is a better look than the hypergammas?
Click to expand...
I've had good results with both, but still haven't compared both on the same shots, meant to do that yesterday but failed! Will try and find some time over the weekend.
 
I've tried to create a custom LUT based on LC709A that bumps the color temperature. Like, say an LC709A+300k or whatever.

What I've found is that Sony's concept of color temp vs. Speedgrade's (which is what I used) is not the same. Raising temp in-camera vs. in post does not produce the same result in my limited testing. This maybe Speedgrade's fault, but it doesn't really matter because the result is still the same. This is why I wanted to use a filter instead, since it's a "tried and true" method from the film days.

I haven't really considered shooting in Custom mode because I haven't had time to really mess with all the settings under Custom, but mostly because I wanted the Sgamut3.Cine/LC709A look. Eventually, I'll look into it, but for now, I just prefer shooting in CineEI.

The real "fix" for the problem is for Sony to allow dialing in white balance in-camera... which I heard was coming, or that they're at least looking into it? Remember someone said this in another thread.
 
I haven't heard that Sony is planning to do it. They've been hearing about the problem since the F5/55 were released with Art Adams among others complaining loudly. What I gather from Alister Chapman is that it would not work well to be doing this at the level of the actual Raw file because it could create color errors in post. However, RED's method and Alexa's was to do it in the Lut's. There may be errors in those Lut's also but at least you get to play with them . I would like to see it, but am not holding my breath as it might require a major re-workingh of the whole LUT system and who knows if there is enough power in the FS7 to handle that.

Have you tried using Resolve to alter the LUT's? I'm way behind in my testing on all this. Hoping you guys can figure out for me :)
 
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