View Full Version : 24f Ghosting


Dave Perry
February 26th, 2008, 03:51 PM
Hello gang,

I'm finally starting to switch to a 24p(f) workflow and have discovered that there is a setting(s) that creates extreme ghosting and trails. I created my own Custom Preset and have not had good results. I switched to AC PREF1 from the library here at DVinfo and get much better results. I'm also trying to get a cool somber look like the outdoor scenes in Children of Men.

Could anyone tell me which settings to be careful with, to avoid ghosting?

Attached is a screen shot of the settings that I came up with, and Alister Chapmans settings for CP #1 in the library.

Thanks.

Daniel Epstein
February 26th, 2008, 04:44 PM
Sounds like the noise reductions in the Custom Preset menu.

Dave Perry
February 26th, 2008, 05:03 PM
So should I not use the noise reduction?

Pete Bauer
February 26th, 2008, 09:26 PM
Would be helpful to see a frame grab or short clip so we don't misunderstand what you're seeing. Could be NR1 one if there is a lot of motion in low light, and you're using it. Going to the Advanced Search page and looking for NR1 in this forum will provide a lot of reading on the subject. Here's a start:

http://www.dvinfo.net/conf/showpost.php?p=803039&postcount=10
http://www.dvinfo.net/conf/showthread.php?t=84881
http://www.dvinfo.net/conf/showthread.php?t=80396
http://www.dvinfo.net/conf/showpost.php?p=534403&postcount=8

Also, what shutter speed are you using? You'd expect that the slower shutter speeds typically used with 24fps shooting are going to give you more motion blur and accentuate the NR1 ghosting. Another gotcha is that using the Cine settings for gamma and color matrix requires greater exposure, and I believe to a lesser extent the same is true for the negative values in the color gains and matrices so if you're struggling with inadquate lighting, might be the lesser of evils to avoid those, even if it means some additional tweaking in post.

Dave Perry
February 27th, 2008, 10:08 AM
Thanks Peter and Daniel. I'm working on some new presets without NR1 and will let you know what happens. In the mean time, I've posted some screen shots and video clips at www.cartermedia.tv/DVinfo_samples

The movie clips are HDV 24p out of FCP Studio 2. The footage was shot in 24f using a Redrock Micro with a Nikon Nikkor S 50mm set at f2.

Camera settings:

Sequence_3_dp.mov and Sequence_3_dp2.mov - AE Shift 0, shutter 1/100, exposure locked and then +1

Sequence_3_dp3.mov - same as above but with shutter at 1/60 and AE Shift +.5

The ghosting is very apparent in red highlights and people's faces. The faces look like they are melting off. Kind of like Tom Cruise's face when he takes that shot in Minority Report. Also notice ghosting in the arm in Sequence_3_dp3.png.

Thanks for the suggestions and help.

Nick Hiltgen
February 27th, 2008, 10:48 AM
is skin detail on?

Dave Perry
February 27th, 2008, 11:15 AM
All Skin Detail settings are at default with the Detail setting off.

Hue - 0
Chroma - 0
Area - 0
Y Level - 0
Skin Detail - off

Dan Keaton
February 27th, 2008, 02:09 PM
Turn off Noise Reduction 1.

This will cause ghosting in low-light conditions.

Do not use Noise Reduction 1 unless you are locked down on a tripod. It is even better to avoid this at all times.

Nick Hiltgen
February 28th, 2008, 02:07 AM
Dan's absolutely right. I didn't look at the settings before I asked my question. Turn of NR1 and then see if ghosting is still there.