I wish for... NEW_3200K_TUNGSTEN_BALANCED_OLPF

[Martin Stevens]

Dear Red and RedUsers,

Perhaps this has been brought up and/or thought of before, but...

Yes, that's right, I wish to have Red or ? make a 3200K Tungsten Balanced OLPF for use with my Red DRAGON etc.

The way I see it, since the STH OLPF already has some sort of ND filter or similar built into it,
I reason that instead of this ND sort of layer, we could have a blue CTB filter sort of layer.
This way my HMIs will look just as blue as when using Tungsten film stock.

And, yes, I know I can process my data at 3200K in Redcine etc., but having a 3200K Tungsten Balanced OLPF
would be very, very nice.

Okay, so I'll take a Carbon 1 filter with 3200K all-in-one OLPF please, and a side order of fries.

 

[Graeme Nattress]

STH is pretty much what you're asking for. But of course the calibration process means you don't see any difference in the kelvin numbers needed to white balance the scene, unlike if you'd used the LLO or STD with added CTB say.

Graeme

 

[Martin Stevens]

STH is pretty much what you're asking for. But of course the calibration process means you don't see any difference in the kelvin numbers needed to white balance the scene, unlike if you'd used the LLO or STD with added CTB say.

Graeme

Thanks for the response Graeme. Could you clarify, as I'm not quite sure what you mean?

I'm asking for an OLPF with CTB built into one of it's layers.

 

[Graeme Nattress]

What I was getting at is if you shoot and put a coloured filter like a CTB to shift the response so that tungsten balances more neutral, that is reflected in the kelvin needed to white balance the scene as 3200k light now balances at 5600k say. But if that filtering is done as part of the OLPF, then I calibrate that response so that 3200k still balances at 3200k, but the very same shifting of the light colour is going on behind the scenes, making the system balance more for tungsten like you want - you just don't see that result reflected in the colour temp you white balance for. Now, STH isn't some CTB sandwiched into the glass - I'm only using the idea of a CTB in front of the lens as an analogy to what is going on. But STH does shift the native white balance of the system away from daylight and towards tungsten, just via different filtration methods than CTB.

Graeme

 

[David Mullen ASC]

You could design a CFA and OLPF to cut the warmer wavelengths and bias the signal to get a stronger exposure for the blue channel, just as in tungsten film stock, where the blue layer is faster and grainier to compensate for the lack of blue wavelengths in 3200K lighting, but I think you'd end up with a much lower ASA rating for the camera.

As with tungsten film stocks where the blue layer is grainier than with daylight stocks, I think you're better off just making a less noisy system overall so that the boosting of the blue channel for 3200K doesn't look objectionably noisy but still would be cleaner in 5500K lighting.

 

[Martin Stevens]

Thanks Graeme and David,

So David, do you no longer find the need to use 80A or 80 B, C, or D type blue filters when using Dragon in Tungsten light
and you wish for the tungsten light to appear as say 5500K light?

And Graeme, what is the native color temp of the STH OLPF? I thought it was 5000K.

 

[Phil Holland]

Thanks Graeme and David,

So David, do you no longer find the need to use 80A or 80 B, C, or D type blue filters when using Dragon in Tungsten light
and you wish for the tungsten light to appear as say 5500K light?

And Graeme, what is the native color temp of the STH OLPF? I thought it was 5000K.

I'm not David, but I've spoken to Graeme time to time over the last couple of years about various things. I haven't needed to use any blue filtration on Dragon whatsoever. When shooting Tungsten with Mysterium-X, especially on VFX/Green Screen shoots, I used filters. After a fair bit of testing I haven't found any true need for it on Dragon.

 

[Christoffer Glans]

I'm really interested in how the new standard OLPF handles these things, how much of the STH color and highlight properties do we loose on that?

 

[Craig Lees]

Hi Graeme,

How about a tungsten OLPF rated at 800ISO that has the same look under tungsten lighting as the STH OLPF?

is that even possible?

: )

Craig Lees
ED & SX UK
3dstories.co.uk

 

[Dustin Veneman]

I recently shot under tungsten on dragon with low light optimized olpf. I had a Tiffen 80D filter but ended up not using it. I was getting a cleaner image without it.

 

[Martin Stevens]

I'm not David, but I've spoken to Graeme time to time over the last couple of years about various things. I haven't needed to use any blue filtration on Dragon whatsoever. When shooting Tungsten with Mysterium-X, especially on VFX/Green Screen shoots, I used filters. After a fair bit of testing I haven't found any true need for it on Dragon.

Thanks Phil.