Jump to content


Photo

desaturation with Varicam


  • Please log in to reply
9 replies to this topic

#1 Valentina Caniglia

Valentina Caniglia
  • Basic Members
  • PipPip
  • 49 posts
  • Cinematographer

Posted 05 January 2006 - 05:20 PM

Dear all,

I am shooting a film in feb. in HD that will be color corrected in telecine or DI projected in HD and if we are lucky to find a distributor we will transfer in film. The director and I are looking for a desaturated look. We will be helped from the production designer to achieve this look.

My first recommendation was to shoot with F900 because the colors of that camera look more desaturated.
We have many exterior shots shooting in the forest and no budget to film with F900 so we may go with Varicam and the pro 35mm adaptor.

Any ideas on how to manipulate the menu on the Varicam and achieve a more desaturated look?

I also wanted to ask about the aspect ratio - I was thinking to shoot on 2.35. Do I have to frame for 2.35 and crop it later?

Thank you in advance

V.
  • 0

#2 Joe Farris

Joe Farris
  • Basic Members
  • PipPip
  • 28 posts
  • Cinematographer
  • Chicago, IL

Posted 05 January 2006 - 05:44 PM

I believe canon makes an anamorphic adaptor but you may have to shoot with HD lenses, the varicam does have 2:35 framing guides so worst case scenario you can frame and crop in post. As far as the de-saturated look goes, the best bet is of course post, however the varicam does have plenty of controls within it's menu to achieve the desired look. Hire a good DIT and you'll have no problem getting what your after. Also get a copy of the Goodman's guide to the varicam. The book will walk you through every setting in the menu. It also comes with a bunch of preset scene files for you to take a look at. One of which is a De-saturated look if I'm not mistaken, I don't have mine in front of me.

Joseph Farris
Director of Photography
Visions of Light, Inc.
Office: 312-829-8244
Pager: 800.808.8244
Mobile: 630.306.8244
Fax: 630.690.7678
www.visionsoflightinc.com
joe@visionsoflightinc.com
  • 0

#3 David Mullen ASC

David Mullen ASC
  • Sustaining Members
  • 19769 posts
  • Cinematographer
  • Los Angeles

Posted 05 January 2006 - 08:00 PM

Yes, the Goodman Guide explains how to reduce the saturation using the camera's Color Matrix menu, pretty simple to do actually.

The simplest and most common method of achieving 2.35 with an HD camera is to crop; the Sony has framelines in the menu for that ("Vista 2") and no doubt the Varicam has some way of generating framelines for that in the viewfinder.

Only thing to test is whether the resolution holds up in a transfer to film, since you are starting out with a 720 line image instead of a 1080 line image. Cropping to 2.35 means your vertical resolution is no better than standard def video. Not to say that the results won't be acceptable though, so test, test, test.
  • 0

#4 Phil Rhodes

Phil Rhodes
  • Sustaining Members
  • 11945 posts
  • Other

Posted 05 January 2006 - 08:17 PM

Hi,

> As far as the de-saturated look goes, the best bet is of course post

I'm not sure that's right with any video camera; the best place to do anything is in the camera's DSP, which has access to unadulterated CCD data and can perform the lowest-noise transformations. The room for change in post is limited, but then that's true of all DSP processed video anyway.

Phil
  • 0

#5 David Mullen ASC

David Mullen ASC
  • Sustaining Members
  • 19769 posts
  • Cinematographer
  • Los Angeles

Posted 05 January 2006 - 09:39 PM

Hi,

> As far as the de-saturated look goes, the best bet is of course post

I'm not sure that's right with any video camera; the best place to do anything is in the camera's DSP, which has access to unadulterated CCD data and can perform the lowest-noise transformations. The room for change in post is limited, but then that's true of all DSP processed video anyway.

Phil


Although I feel that reducing the chroma in post tends to be less artifacty than pushing the chroma in post, so if you're not sure, it may be safer to leave desaturation until post.
  • 0

#6 Michael Collier II

Michael Collier II
  • Guests

Posted 05 January 2006 - 09:41 PM

I'm not sure that's right with any video camera; the best place to do anything is in the camera's DSP



I would dissagree only in regards to desat (dont think I am saying you'd be wrong across the board, for anything but desat your right)

Every camera I can think of records luminence in full resolution. This value will not change regardless of saturation. When you try and increase saturation noise is added quite rapidly in my experience, but when you take saturation away, your just turning down the Cr and Cb levels. If you are quanatizing those at 8bit lets say, you have a value of 169 lets say for Cr and 201 for Cb. If you want to cut those in half in post you would arive at values of 84.5 and 100.5 respectivley. Now if you do it in DSP at 12 bit the equivalent values would be 2703(.36 but its digital, so round down) out of 4096 (12 bit, 66IRE equivalent) and a Cb value of 3216 (78.5 IRE)

Now take those values and apply the same 1/2 desat algorythm. you get a Cr/Cb value of 1351.5 and 1608 respectivley. transform those to 8bit to match the NLE's 8 bit codec (or the tapes 8bit codec) you get and 100.5 and 84.46875.

You can see that desat does not in fact add any noise. Saturation up does add considerable noise

SO

After the mathematicle eval (which few actually read im sure,) you can see there is no noise introduced. I submit this to you: what if you desat in DSP, But in post you decide to turn the sat up (either because you dont like the image as desat as you got from DSP or to match one camera shot to another) you are actually introducing much more noise to the equation than if you had done a baseline factory saturation level from the beginning.

*things to note:
This only includes linear desaturation, where all colors are desaturated at the same rate. I am not sure if this same equation applies to a desat applied to various colors (IE bringing red sat down 75% and blue sat 25%) I am not sure the actuall equation for this (depends on the NLE you are using) but from experience I have noticed no noise induced from even this (unless you up-sat one of the channels) and trust me I am very particular about my colors and noise levels.

I hope this makes sense and hasnt confused anyone. Remember this only applies to sat-down accross the board. Other color correction effects I aggree should be done in camera if possible. Desat mathematically however does not represent a noise problem. essentially you are throwing information out in a linear fasion, and keeping all info in the luma track. this is not affected by the color space rendering (ie 4:4:4, 4:2:2, maybe in 4:1:1 I would watch out, but in all the DV editting I have done I have not seen any effect, I just havent done the math to prove 4:1:1 does not provide a problem)
  • 0

#7 Frank Barrera

Frank Barrera
  • Sustaining Members
  • 465 posts
  • Cinematographer
  • Los Angeles, CA

Posted 05 January 2006 - 10:09 PM

If you plan on ever going to film you should be cautious with using the 35mm adaptor. the decrease in sharpness may be undesirable especially if you are cropping for 2.35 and losing resolution.


yes test


and have fun

Frank Barrera
  • 0

#8 Valentina Caniglia

Valentina Caniglia
  • Basic Members
  • PipPip
  • 49 posts
  • Cinematographer

Posted 05 January 2006 - 11:11 PM

Thank You to all about your advises.

I will definetly test and will work with my DIT to make desaturation in camera. I always like to do more in camera than in post.

Since Frank Barrera mentioned about transfer the HD footage shot with pro 35mm to film will decrease the sharpness. I would like to know more about this issue. I shot already with pro 35mm but never transfer to film. Any concerns that I should be aware of?

Thanks again

V.
  • 0

#9 Michael Collier II

Michael Collier II
  • Guests

Posted 06 January 2006 - 01:58 AM

Well its aproxamatley the equivalent of a 1/8th promist, from what I understand. Add to that your only shooting in 720p which will make it even softer. I would not shoot with it until you test it on the stock you plan to output to. better off spending cash up front then getting a soft/blurred look. (i dont know if it will be too soft, or look like a nice 1/4 promist, so test)
  • 0

#10 Phil Rhodes

Phil Rhodes
  • Sustaining Members
  • 11945 posts
  • Other

Posted 06 January 2006 - 07:24 AM

Hi,

It depends how the colour corrector calculates saturation. Most of them operate in RGB space (as they're intended to work on uncompressed film scans, which tend to be RGB) and they will calculate luma as a weighted average of red, green and blue. This can introduce noise, blockiness and compression artifacts from the low-resolution UV axes of a video image.

Phil
  • 0


The Slider

CineLab

rebotnix Technologies

Rig Wheels Passport

Aerial Filmworks

Tai Audio

Gamma Ray Digital Inc

Wooden Camera

Metropolis Post

Ritter Battery

Willys Widgets

Paralinx LLC

Broadcast Solutions Inc

Glidecam

Abel Cine

Visual Products

Opal

Media Blackout - Custom Cables and AKS

CineTape

Technodolly

FJS International, LLC

Broadcast Solutions Inc

Paralinx LLC

Opal

CineLab

Abel Cine

Tai Audio

Aerial Filmworks

Wooden Camera

Ritter Battery

Willys Widgets

Gamma Ray Digital Inc

Rig Wheels Passport

FJS International, LLC

rebotnix Technologies

Visual Products

Media Blackout - Custom Cables and AKS

The Slider

Metropolis Post

CineTape

Technodolly

Glidecam