Flicker or Shimmer at DVinfo.net

Paul Robertson · October 1st, 2003, 09:30 PM

Hi, I'm a newcomer to using digital video cameras and obviously have, and will have from time to time, many questions relating to video filming. Having got my new NV-GS100K up and working I noticed than on playback (on various newish TVs) there was quite a a bit of 'flicker' or 'shimmer' or 'waves' in some situations where there was a major difference in contrast or brightness. This also seems to occur more when panning (even very slowly). I had filmed on auto (default) setting, fairly early in the morning so the contrast and brightness may have been a problem. The colors also seemed particulary sharp. Similar effects occurred
when filming indoors. Any ideas on how to overcome this problem?

Thanks

Paul

Frank Granovski · October 1st, 2003, 10:49 PM

Quote:

on playback (on various newish TVs) there was quite a a bit of 'flicker' or 'shimmer' or 'waves' in some situations where there was a major difference in contrast or brightness. This also seems to occur more when panning (even very slowly).

In "auto," the sensors (or eyes) are deciding what to focus and what to white balance.

Paul Robertson · October 1st, 2003, 11:41 PM

Thanks for that. Someone with a little more knowledge than me has had a look at the video I shot and described the phenomen as "zebra" which is particulary noticeable in 'white' areas.

Yow Cheong Hoe · October 2nd, 2003, 03:07 AM

Ooops, "zebra" is a feature to inform the camera user that there is over-exposure (overload of the CCD input) and the signal is clipped.

Zebra is only on the viewing screen (LCD or EVF) and can be turned on or off. Certainly not recorded in the tape.

Andre De Clercq · October 2nd, 2003, 07:31 AM

Paul, some areas in Japan (Tokyo and eastern areas) have 50Hz mains and NTSC framerates. High brightness zones on TV are known to show area flicker at these refresh rates. Also interline flicker and line crawl are some artifacts which are well known with CRT displays. Look for a 100Hz TV if this is yr problen

Paul Robertson · October 2nd, 2003, 03:53 PM

Thanks Andre. I'll look into that too. I noticed yesterday afternoon when I tried some further shooting (still in auto mode) that the distortions could also be seen through both the camera viewfinder and on the LED before shooting, which makes me wonder if it's a problem specific to that particular camera.

Regards,

Paul

Frank Granovski · October 2nd, 2003, 04:41 PM

Why not go to a local shop and see if you can duplicate your concerns with a display model or 2, to determine what your next step will be. Please post your findings here.

Paul Robertson · October 2nd, 2003, 05:27 PM

Hi Frank,

Yes that will be my next step. I'll do that this weekend and post my findings.

Thanks,

Paul

Andre De Clercq · October 3rd, 2003, 03:26 AM

Paul, if you only get this problem in auto mode and not in (well exposed) manual mode it could turn out that there is an hunting phenomenon in the camera's auto exposure system. Also, if you look at a (VHS) copied version. the VCR video autogain controls tend to show this effect when the applied signal levels are too high or with a sudden change in the average picture level

Paul Robertson · October 7th, 2003, 04:29 AM

Well, I took the camera back to the store on the weekend, and the staff agreed that the camera was somewhat faulty and have replaced it. They did say that some shimmer, zebra effect, etc under certain light conditions is fairly common on digital video cameras, but that being experienced on mine was excessive. So, the next step is to try this new one out extensively over the next weekend. Hopefully I won't be disappointed! Thanks for your help everyone.

Frank Granovski · October 7th, 2003, 04:39 AM

Paul, way to go. Let us know how this new one works for you. :)

October 1st, 2003, 09:30 PM	#1
Paul Robertson New Boot Join Date: Sep 2003 Location: Tokyo Posts: 5	Flicker or Shimmer Hi, I'm a newcomer to using digital video cameras and obviously have, and will have from time to time, many questions relating to video filming. Having got my new NV-GS100K up and working I noticed than on playback (on various newish TVs) there was quite a a bit of 'flicker' or 'shimmer' or 'waves' in some situations where there was a major difference in contrast or brightness. This also seems to occur more when panning (even very slowly). I had filmed on auto (default) setting, fairly early in the morning so the contrast and brightness may have been a problem. The colors also seemed particulary sharp. Similar effects occurred when filming indoors. Any ideas on how to overcome this problem? Thanks Paul

October 2nd, 2003, 03:07 AM	#4
Yow Cheong Hoe Major Player Join Date: Nov 2002 Location: Singapore, Passport: Malaysia Posts: 407	Ooops, "zebra" is a feature to inform the camera user that there is over-exposure (overload of the CCD input) and the signal is clipped. Zebra is only on the viewing screen (LCD or EVF) and can be turned on or off. Certainly not recorded in the tape. __________________ Cam: Panasonic MX350EN, SOLD my MX8EN Mac: G3 400MHz PowerBook, 256 MB, OS 9 PC: Pentium 4 2800MHz, 512 MB, WindowsXP SW: iMovie, Final Cut Pro, Adobe Premiere, Ulead Video Studio, various little utilities

October 1st, 2003, 11:41 PM	#3
Paul Robertson New Boot Join Date: Sep 2003 Location: Tokyo Posts: 5	Thanks for that. Someone with a little more knowledge than me has had a look at the video I shot and described the phenomen as "zebra" which is particulary noticeable in 'white' areas.

October 2nd, 2003, 07:31 AM	#5
Andre De Clercq Major Player Join Date: Sep 2002 Location: Belgium Posts: 804	Paul, some areas in Japan (Tokyo and eastern areas) have 50Hz mains and NTSC framerates. High brightness zones on TV are known to show area flicker at these refresh rates. Also interline flicker and line crawl are some artifacts which are well known with CRT displays. Look for a 100Hz TV if this is yr problen

October 2nd, 2003, 03:53 PM	#6
Paul Robertson New Boot Join Date: Sep 2003 Location: Tokyo Posts: 5	Thanks Andre. I'll look into that too. I noticed yesterday afternoon when I tried some further shooting (still in auto mode) that the distortions could also be seen through both the camera viewfinder and on the LED before shooting, which makes me wonder if it's a problem specific to that particular camera. Regards, Paul

October 2nd, 2003, 04:41 PM	#7
Frank Granovski Outer Circle Join Date: May 2002 Location: Hope, BC Posts: 7,524	Why not go to a local shop and see if you can duplicate your concerns with a display model or 2, to determine what your next step will be. Please post your findings here.

October 2nd, 2003, 05:27 PM	#8
Paul Robertson New Boot Join Date: Sep 2003 Location: Tokyo Posts: 5	Hi Frank, Yes that will be my next step. I'll do that this weekend and post my findings. Thanks, Paul

October 3rd, 2003, 03:26 AM	#9
Andre De Clercq Major Player Join Date: Sep 2002 Location: Belgium Posts: 804	Paul, if you only get this problem in auto mode and not in (well exposed) manual mode it could turn out that there is an hunting phenomenon in the camera's auto exposure system. Also, if you look at a (VHS) copied version. the VCR video autogain controls tend to show this effect when the applied signal levels are too high or with a sudden change in the average picture level

October 7th, 2003, 04:29 AM	#10
Paul Robertson New Boot Join Date: Sep 2003 Location: Tokyo Posts: 5	Well, I took the camera back to the store on the weekend, and the staff agreed that the camera was somewhat faulty and have replaced it. They did say that some shimmer, zebra effect, etc under certain light conditions is fairly common on digital video cameras, but that being experienced on mine was excessive. So, the next step is to try this new one out extensively over the next weekend. Hopefully I won't be disappointed! Thanks for your help everyone.

October 7th, 2003, 04:39 AM	#11
Frank Granovski Outer Circle Join Date: May 2002 Location: Hope, BC Posts: 7,524	Paul, way to go. Let us know how this new one works for you. :)