Jump to content


XDCam red edging


  • Please log in to reply
4 replies to this topic

#1 Benjamin Pritchard

Benjamin Pritchard
  • Guests

Posted 05 September 2012 - 05:07 AM

During a recent shoot using a Sony PMW500 set to 422 50mbps MPEG2 I was looking to shoot a character in front of a completely blown out window. I used no fill as I wanted over expose the image till the entire (large) window had blown to white. I found that up to a point the image was fine until blowing the last of the detail seen through the window. A red edge appeared all around my foreground subject much like a solid red ghost image. The red had distinct boundaries rather than feathering into the shadow detail.
Has anyone come across this and how might it be controlled. Given the hectic nature of the shoot I left a bit of detail in the window and exposed to just before the red appeared so that the windows might be further blown in post. I would imagine that clipping the whites might have worked but couldn't get it working on the day.
Is this particular to the camera system used or an HD issue in general.

Benjamin
  • 0

#2 Ari Davidson

Ari Davidson
  • Basic Members
  • PipPipPip
  • 124 posts
  • Cinematographer

Posted 05 September 2012 - 07:30 AM

During a recent shoot using a Sony PMW500 set to 422 50mbps MPEG2 I was looking to shoot a character in front of a completely blown out window. I used no fill as I wanted over expose the image till the entire (large) window had blown to white. I found that up to a point the image was fine until blowing the last of the detail seen through the window. A red edge appeared all around my foreground subject much like a solid red ghost image. The red had distinct boundaries rather than feathering into the shadow detail.
Has anyone come across this and how might it be controlled. Given the hectic nature of the shoot I left a bit of detail in the window and exposed to just before the red appeared so that the windows might be further blown in post. I would imagine that clipping the whites might have worked but couldn't get it working on the day.
Is this particular to the camera system used or an HD issue in general.

Benjamin


Sounds like aliasing due to the bayer pattern.
Post a sample?
  • 0

#3 Benjamin Pritchard

Benjamin Pritchard
  • Guests

Posted 13 September 2012 - 01:19 AM

Here are some examples of the red edging discussed above. Test 1 is shot at f.16 and test 6 at f.1.8. the issue becomes progressively worse the more over exposed the image. Admittedly I couldn't imagine wanting to over expose more than test 1 in this case but I did before and would like to know why I can't.

Attached Images

  • test01.jpg
  • test02.jpg
  • test03.jpg
  • test04.jpg
  • test05.jpg
  • test06.jpg

  • 0

#4 Andre Labous

Andre Labous
  • Basic Members
  • PipPip
  • 39 posts
  • Cinematographer
  • Neptune Beach, FL

Posted 13 September 2012 - 04:35 PM

Benjamin,
I had similar problem with my PMW-500 using a Canon HJ 4.7x11 lens. It my case the chromatic aberration problem created blue lines in edges from extreme over exposure on horizontal and vertical lines. The PMW 500 has Automatic Lens Aberration Compensation. In menus make sure you have right lens selected. My problem was finally solved when I sent my lens back to canon and had latest firmware installed so that the 500 could recognize the lens thus adjusting aberration.
Hope that helps,
Andre
  • 0

#5 Benjamin Pritchard

Benjamin Pritchard
  • Guests

Posted 16 September 2012 - 11:57 PM

Here is a still from the original footage. Of particular alarm is the red line emanating from the left side of the frame. Was this similar to the blue edging seen?

Attached Images

  • Screen Shot 2012-09-13 at 4.43.25 PM.png

  • 0


Paralinx LLC

Broadcast Solutions Inc

Abel Cine

Aerial Filmworks

FJS International, LLC

rebotnix Technologies

Wooden Camera

Technodolly

Glidecam

CineLab

Rig Wheels Passport

Ritter Battery

Tai Audio

Willys Widgets

CineTape

Metropolis Post

The Slider

Opal

Media Blackout - Custom Cables and AKS

Visual Products

Gamma Ray Digital Inc

Broadcast Solutions Inc

rebotnix Technologies

Paralinx LLC

Gamma Ray Digital Inc

Aerial Filmworks

Abel Cine

Media Blackout - Custom Cables and AKS

Tai Audio

Technodolly

Ritter Battery

Glidecam

Opal

Wooden Camera

Visual Products

Willys Widgets

CineTape

The Slider

Rig Wheels Passport

Metropolis Post

FJS International, LLC

CineLab