Jump to content


Photo

DCC on or off?


  • Please log in to reply
7 replies to this topic

#1 Simon Wyndham

Simon Wyndham
  • Basic Members
  • PipPipPip
  • 146 posts
  • Camera Operator
  • UK

Posted 25 May 2005 - 11:00 AM

In light of several articles regaring HD shooting stating that DCC should always be turned on, I have also found some opinion that states that they always use DCC (Dynamic Contrast Control) with caution due to its automation and 'hunting' effects that can sometimes come with it.

What is the general concensus here regarding DCC? Would you only recommend it for highly controlled lighting conditions, or would you risk it in more unpredictable situations?
  • 0

#2 Laurent Andrieux

Laurent Andrieux
  • Sustaining Members
  • 1527 posts
  • Cinematographer
  • France

Posted 25 May 2005 - 11:42 AM

>caution due to its automation and 'hunting' effects that can sometimes come with it.

Very interesting topic, actually.

I don't know aspecially for HD, but I have noticed that the so called "DCC" or "Auto Knee" at pansonic's automated circuitry have a reverse to the medal :

I don't consider there is much noise powered by this circuitry, actually, so I think that from this point of view, it's not a problem keeping it on... but...

I think one should check the default values of the automated function, (that being just as complicated to do as to set your own parameters...), before shooting because I have found situations - that are typical of this use : ITW in the shade with a highlight sky and trees in the very background - where turning it off would give me better details than turning it on...

It's a bit the same with flare correction... When it's on (by default), you might power the blacks when no backlight (out of frame) or whatever flaring situation, so that when you protect the lens with a flag for instance, you get more flare than leaving the lens liten by the source with the flare correction on... It's like if the correction would work good in a flary situation, and doesn't when you protect the lens, so the flare correction is stronger when done by the circuitry itself, better than prtecting the lens... May be linked to some ABL-like circuitry as well...

Edited by laurent.a, 25 May 2005 - 11:43 AM.

  • 0

#3 David Mullen ASC

David Mullen ASC
  • Sustaining Members
  • 19765 posts
  • Cinematographer
  • Los Angeles

Posted 25 May 2005 - 12:59 PM

I've never seen the DCC (Auto Knee) "hunting" or changing visibly in mid-shot myself. I usually leave it on in order to reduce clipping problems.

However, you should always double-check in scenes with a lot of overexposure or bright highlights because you may prefer the look with DCC turned off actually. With the earlier F900, DCC was pretty mild, but with the /3 upgrade, the DCC is more powerful and sometimes too effective, making overexposed patches look "dulled down" and compressed, like you're getting dirty whites. I once shot on a white cyc and had to turn off the DCC because otherwise I was seeing every dirt spec on the white walls -- in other words, it wasn't clipping FAST enough for my tastes! Sometimes compressed bright areas looks just as weird as clipped areas, so keep an eye on the effect.

However, you'll find most of the time that DCC is a good thing because it holds bright detail more naturally. Like I said, I've never seen it make a visible adjustment in mid-shot that calls attention to itself -- it's rarely "late" as you pan past a window or something.
  • 0

#4 Stephen Williams

Stephen Williams
  • Sustaining Members
  • 4708 posts
  • Cinematographer
  • Europe

Posted 25 May 2005 - 01:09 PM

I've never seen the DCC (Auto Knee) "hunting" or changing visibly in mid-shot myself. I usually leave it on in order to reduce clipping problems.

<{POST_SNAPBACK}>


Hi,

I was shooting a night scene and when an actor lit a match the DCC was hunting for a few frames. Luckily I new what the problem was.

Stephen
  • 0

#5 Tim J Durham

Tim J Durham
  • Sustaining Members
  • 742 posts
  • Director
  • East Coast, Baby!

Posted 25 May 2005 - 02:08 PM

With the earlier F900, DCC was pretty mild, but with the /3 upgrade, the DCC is more powerful and sometimes too effective, making overexposed patches look "dulled down" and compressed, like you're getting dirty whites. I once shot on a white cyc and had to turn off the DCC because otherwise I was seeing every dirt spec on the white walls -- in other words, it wasn't clipping FAST enough for my tastes!

<{POST_SNAPBACK}>


In every Sony camera I've used since they first offered DCC (BVW-300 had it and IIRC so did the BVP-7), the white clip has been adjustable (by opening the side of the camera). Now it is in the engineering menus (atleast the DSR-570 and the DVW-700 and 790) and you can customize how you want it to respond by working on your knee (point, slope, saturation) levels and your white clip level. So if you don't like the heavier effect of the current (3) upgrade, I suspect you can get it to work they way you like it in the menus.

Paul Wheeler suggests setting the knee saturation to -50 on the DVW-790 to match the less strident effect that the DVW-700 DCC had. Knowing how Sony does things, it is likely a similar
difference between the two releases of the F-900.
  • 0

#6 Patrick Neary

Patrick Neary
  • Basic Members
  • PipPipPipPip
  • 873 posts
  • Cinematographer
  • Portland, OR

Posted 25 May 2005 - 02:12 PM

hi there-

it may also depend on the individual manufacturer- I've always used DCC on with Sony beta and digibeta cameras, but am very careful about using it with a JVC dv5000- there can be a very noticeable fluctuation.
  • 0

#7 Alvin Pingol

Alvin Pingol
  • Basic Members
  • PipPipPipPip
  • 677 posts
  • Student
  • California

Posted 28 May 2005 - 07:06 PM

>>the DCC is more powerful and sometimes too effective, making overexposed
>>patches look "dulled down" and compressed, like you're getting dirty whites.

>>I've always used DCC on with Sony beta and digibeta cameras, but am very
>>careful about using it with a JVC

I leave DCC disabled on my pro-sumer JVC (model GY-DV300) for the very reason Mr. Mullen mentions; it seems a bit too strong and, this being a pro-sumer model, is unadjustable, unfortunately. What would be clipped highlights, i.e. 100IRE white, appear as white with a mild tint - not quite sure how the auto-knee decides what kind of chroma information it will "save," though I've had problems dealing with what seemed like random choices: purple/magenta tint seems to be a popular choice for the circuitry.

Additionally, for those like myself who rely heavily on zebra stripes to determine optimum exposure settings (especially in uncontrolled and/or outdoor lighting situations), stripes show after auto-knee has done its work. Thus, if one sets zebras to 90IRE (for example), planning on not letting highlights go hotter than that, one runs the risk of overexposing because it'll appear that the highlights are still in check, when in reality it is just the auto-knee trying to save some chroma information.

Of course, to base exposures off of zebra settings requires that you know your camera's response curve rather well in the first place.
  • 0

#8 Phil Rhodes

Phil Rhodes
  • Sustaining Members
  • 11941 posts
  • Other

Posted 29 May 2005 - 06:30 AM

Hi,

I think this is all one more reason why we need straight-off-the-CCD Viper style recording.

Phil
  • 0


Technodolly

Metropolis Post

Ritter Battery

Wooden Camera

Opal

Willys Widgets

rebotnix Technologies

Broadcast Solutions Inc

CineTape

Visual Products

CineLab

Rig Wheels Passport

Abel Cine

FJS International, LLC

Tai Audio

Media Blackout - Custom Cables and AKS

Paralinx LLC

Aerial Filmworks

Glidecam

Gamma Ray Digital Inc

The Slider

Wooden Camera

Media Blackout - Custom Cables and AKS

Visual Products

rebotnix Technologies

Willys Widgets

The Slider

Glidecam

Gamma Ray Digital Inc

CineLab

Ritter Battery

Rig Wheels Passport

Broadcast Solutions Inc

CineTape

Tai Audio

Metropolis Post

Technodolly

Paralinx LLC

Aerial Filmworks

FJS International, LLC

Abel Cine

Opal