interference at DVinfo.net

Eric A Robinson · July 16th, 2005, 02:14 AM

HI there
I am experiencing the same problem on two XL'2 so if any one can throw some light on this I would be grateful.

I am shooting various demonstrations which require some very close up shots from both cams. When I have been capturing the footage, I am noticing what looks like analogue type interference, not pixilation but good old fashioned jaggy lines!

The periods of this interference appear to coincide with changes in the shot.

I am using Sony tapes and XL2's with standard 20x lens, 25p/1/50

The strange thing is in Final Cut I don't see the interference on my mac 23" lcd display but it is there on my crt monitor.

any thoughts?

Robin Davies-Rollinson · July 16th, 2005, 02:53 AM

Eric,

Do you think that you are seeing interlace patterns (the "combing" effect)?
Especially since they are not visible on the LCD monitor - only on a CRT.

Robin

Steve House · July 16th, 2005, 02:58 AM

Quote:

Originally Posted by Eric A Robinson

HI there
I...
The periods of this interference appear to coincide with changes in the shot.

I...

What do you mean by "changes in the shot?" Subject moverment, camera movement, or camera start/stop?

Eric A Robinson · July 16th, 2005, 03:18 AM

Hi there

The changes are in camera focus, and operation of the zoom presets.

Lauri Kettunen · July 16th, 2005, 04:00 AM

Eric, do you shoot using the interlaced mode of the XL2? If there's something moving in the image and you shoot an interlaced video, then, often, jaggy lines appear on a computer monitor.

To get a better idea what you really have on tape, connect your XL2 to a TV with a svhs cable. If you still see jaggy lines, then there's a good reason to assume something is wrong.

Eric A Robinson · July 17th, 2005, 11:43 AM

Hi there

It looks like the answer to the problem lies not with the footage but with the crt monitors I am using (panasonic).
It appears that it may be a sync issue betwen the monitors and video signal, as I am shooting in 25p. What leads me in that direction is that the interference is not displayed on the two LCD screens I have on my system, only on the crt screen.

many thanks for your responses.

Steve House · July 17th, 2005, 01:30 PM

Quote:

Originally Posted by Eric A Robinson

Hi there

It looks like the answer to the problem lies not with the footage but with the crt monitors I am using (panasonic).
It appears that it may be a sync issue betwen the monitors and video signal, as I am shooting in 25p. What leads me in that direction is that the interference is not displayed on the two LCD screens I have on my system, only on the crt screen.

many thanks for your responses.

5 will get you 10 the CRT wants interlaced signals only.

Ash Greyson · July 17th, 2005, 09:03 PM

It may be in the footage, just not as pronounced as on the monitor... Easy fix... less of a problem on PAL in general but... in your custom settings, be sure to set the vertical detail to LOW when you are in progressive (25p or 30p) mode. You may also want to turn the sharpness and/or coring down a notch or 2.

ash =o)

Eric A Robinson · July 18th, 2005, 02:30 AM

I am shooting in PAL, and I will try out your advice and let you know what happens.

many thanks

July 16th, 2005, 02:14 AM	#1
Eric A Robinson Regular Crew Join Date: Jan 2005 Location: Edinburgh, Scotland Posts: 82	interference HI there I am experiencing the same problem on two XL'2 so if any one can throw some light on this I would be grateful. I am shooting various demonstrations which require some very close up shots from both cams. When I have been capturing the footage, I am noticing what looks like analogue type interference, not pixilation but good old fashioned jaggy lines! The periods of this interference appear to coincide with changes in the shot. I am using Sony tapes and XL2's with standard 20x lens, 25p/1/50 The strange thing is in Final Cut I don't see the interference on my mac 23" lcd display but it is there on my crt monitor. any thoughts? Last edited by Eric A Robinson; July 16th, 2005 at 02:20 AM. Reason: extra info

July 17th, 2005, 11:43 AM	#6
Eric A Robinson Regular Crew Join Date: Jan 2005 Location: Edinburgh, Scotland Posts: 82	Possible answer? Hi there It looks like the answer to the problem lies not with the footage but with the crt monitors I am using (panasonic). It appears that it may be a sync issue betwen the monitors and video signal, as I am shooting in 25p. What leads me in that direction is that the interference is not displayed on the two LCD screens I have on my system, only on the crt screen. many thanks for your responses.

July 18th, 2005, 02:30 AM	#9
Eric A Robinson Regular Crew Join Date: Jan 2005 Location: Edinburgh, Scotland Posts: 82	Good advice I am shooting in PAL, and I will try out your advice and let you know what happens. many thanks

July 16th, 2005, 02:53 AM	#2
Robin Davies-Rollinson Trustee Join Date: Dec 2002 Location: Gwaelod-y-garth, Cardiff, CYMRU/WALES Posts: 1,215	Eric, Do you think that you are seeing interlace patterns (the "combing" effect)? Especially since they are not visible on the LCD monitor - only on a CRT. Robin

July 16th, 2005, 03:18 AM	#4
Eric A Robinson Regular Crew Join Date: Jan 2005 Location: Edinburgh, Scotland Posts: 82	Hi there The changes are in camera focus, and operation of the zoom presets.

July 16th, 2005, 04:00 AM	#5
Lauri Kettunen Major Player Join Date: Aug 2004 Location: Kangasala, Finland Posts: 445	Eric, do you shoot using the interlaced mode of the XL2? If there's something moving in the image and you shoot an interlaced video, then, often, jaggy lines appear on a computer monitor. To get a better idea what you really have on tape, connect your XL2 to a TV with a svhs cable. If you still see jaggy lines, then there's a good reason to assume something is wrong.

July 17th, 2005, 09:03 PM	#8
Ash Greyson Trustee Join Date: May 2003 Location: Tulsa, OK Posts: 1,689	It may be in the footage, just not as pronounced as on the monitor... Easy fix... less of a problem on PAL in general but... in your custom settings, be sure to set the vertical detail to LOW when you are in progressive (25p or 30p) mode. You may also want to turn the sharpness and/or coring down a notch or 2. ash =o)