Incorrect colour levels from Panasonic DV camera?

Kev-k wrote on 1/9/2010, 4:15 AM
This is a NOOB question, but I am very confused about colour settings when working with PAL DV footage from my Panasonic NV-GS230EB camera. I have been reading up and I don’t believe what I am seeing is correct. It looks to me like the camera is producing computer RGB levels.

As an example, Vegas Pro 8 or 9 [does not seem to matter], 8 bit colour project, I take a PAL DV clip acquired from the camera with the Sony capture program and drop this onto the timeline.

If I open up the RGB Parade on the clip I am seeing RGB levels right down to zero and right up to 255. If I understand things correctly that should not be case? I thought that PAL DV should be recorded in and decode to studio RGB?

It seems to me the only way to get the colours correct is to apply computer to studio levels FX to the clips.

I started looking at this because I was trying to setup my system correctly and do some basic monitor calibration, but when doing this I end up with the footage from the camera looking truly awful, but if I convert things to studio RGB things look at lot better. I am viewing on a secondary Windows monitor that is setup with the studio to computer RGB conversion option.

Any ideas, or is this just a problem with this cheapish old consumer camera... I am seriously looking at upgrading to a decent consumer or prosumer camera, but maybe not quite yet (but if people have suggestions for something in the £1500, (maybe up to £2000) range I would be interested in their feedback)...

Thanks
Kevin

Comments

farss wrote on 1/9/2010, 5:20 AM
Pretty well all cameras record whites upto 109%. My EX1 does this by design, two of the Cinegamma curves record 100% at 100 and 400% at 109% so don't think buying a new camera will avoid this issue.

What is unusual is have the blacks go below 0%, by that I mean being at 0 not 16. I've never seen a camera do that and I just checked footage from a couple, including a very dodgy "DVD' camera. The scopes do show a little part of the waveform below 0% but that's because this camera records 704x576 instead of 720x576 and the 05 black is from the black bars.

If your camera is not actually recording black below 0% then applying a ComputerRGB to StudioRGB tranform is wrong, it'll lift the blacks up into grey and you may not notice this easily on a LCD monitor.

Glenn Chan's site has lots of info on this and how to best deal with it. It really depends on exactly what the camera is doing and how you want to handle say the highlights. Do you want to preserve all the detail in them or do you want to clip them etc.

http://www.glennchan.info/articles/articles.html

Bob.
Kev-k wrote on 1/9/2010, 5:52 AM
OK - so if I understand this correctly the problem is more with the exposure rather than the camera itself.... I should aim for a better exposure balance with lower white levels which should help things out... If I need to adjust in Vegas I should be lowering the white levels (output end in levels LX). The footage was on auto exposure, but there are manual controls to adjust things.

Looking at the RGB parade again it is mainly at the white end that things are high and clipping at 255, but I do see (mainly blue) levels down to near zero (less than 16) on certain clips, but in general the blacks tail off before 16,
TLF wrote on 1/9/2010, 8:26 AM
Yes, it's confusing... make sure that the settings for your waveform monitor are:
UNCHECKED: 7.5 IRE setup (this is not needed for PAL video)
CHECKED: Studio RGB

You will see some whites that extend to around 110%, but these are the superwhites, and with some tweaking you may be able to extract useful information from them.

You can apply the Broadcast Colors plug-in and set it to Extremely Conservative; that will bring the whites down to 100%
GlennChan wrote on 1/9/2010, 8:28 AM
I believe what you're seeing is normal?

This article has info on dealing with superwhites:
http://www.glennchan.info/articles/vegas/color-correction/tutorial.htm

I hope that helps.

---------------
EDIT: to add on....

You may see a few values below 16. This is usually from noise.... e.g. compression noise.

Seeing illegal values above 235 is normal. I don't totally agree with this practice, but cameras will record these illegal values.

At the edges of the frame, you might see values near 0... you need to ignore that when looking at your levels (e.g. crop out the edges or zoom into the image temporarily).