Mystery image shake at DVinfo.net

Patrick Lipawen · December 21st, 2003, 08:41 AM

Hello,

We are using an XL1S and a cheaper Panasonic PVDV52 with an MXPro mixer - this is a broadcast setup for a closed-circuit TV program.

The image from the XL1S shakes very slightly (but noticeably) when the camera is just sitting on the tripod. This occurs whether the stabilizer is on or off. There is nothing moving in front of the camera - just a still shot of a Bingo board or wall decorations.

The image from the Panasonic (or from our other cheaper camera, a Canon ZR40) is perfectly still. We've tried exchanging cables, and switching inputs on the mixer, to no avail.

Anyone know what might be causing the shake? Thanks for any help.

Patrick Lipawen

Frank Granovski · December 21st, 2003, 02:48 PM

It's a stable tripod? Leave OIS disengaged. There could be slight shaking you cannot see, or perhaps the auto sensors are having trouble in lower light.

Patrick Lipawen · December 21st, 2003, 03:39 PM

We have the Libec LS35. The shake occurs with or without the stabilizer. I'm fairly certain the ground is not shaking from construction or large objects being moved about. Also, we are broadcasting from a well-lit area.

Any other ideas? Thanks in advance.

Patrick

Andre De Clercq · December 21st, 2003, 03:46 PM

Are both cams connected to the mixer and a monitor, when you see the problem?

Andre De Clercq · December 21st, 2003, 03:59 PM

Is the shaking only horizontal? Is it periodic?

Patrick Lipawen · December 21st, 2003, 04:20 PM

Yes, we connect both cameras to the mixer. From the mixer, one video out goes to a preview monitor, the other goes into a modulator for our closed-circuit system.

The shaking with the XL1S is vertical, and it is constant. We can see it on the preview monitor, and everyone watching can see it when they turn on our house cable channel. It is only a slight movement, but I would like to get rid of it. Any suggestions?

Patrick

Ken Tanaka · December 21st, 2003, 04:39 PM

To eliminate variables, try disconnecting the XL1s from the mixer and see if the image is stable direct to monitor.

Don Palomaki · December 22nd, 2003, 05:07 AM

How fast is the shake? How large is it. If about one line, it might be an issue in the mixer.

Jeff Donald · December 22nd, 2003, 07:31 AM

Most of the newer mixers use a frame synchronizer to mix the footage. However, the MXPro uses a TBC. Have you upgrade the mixer to use DV or are you using analog in? How long of a cable from the camera to the mixer? I think Ken, Andre and Don are on the right track. Do as Ken suggested and connect the camera directly to a monitor and check for any visible shake. If none is observed, then the mixer is the most likely cause. I would talk to Videonics and see what they suggest.

Patrick Lipawen · December 22nd, 2003, 11:11 AM

There is no shake when the XL1S is attached directly to the monitor. We didn't buy the digital upgrade, so we are using analog inputs. Our RCA cable is 6 ft long.

I guess it is a mixer issue. I will go through our mixer settings and see if I can fix it. I'm not sure why the smaller miniDV cams don't have the same problem.

Thanks for the replies!

Patrick

Rob Easler · December 22nd, 2003, 11:22 AM

Patrick, try to disengage the auto focus and see if it's still there. Sometimes there can be an effect that might resemble shaking if the auto focus is constantly seeking. It's probably not your issue but as none of us can see it, it's hard to judge and it's worth a shot.

Andre De Clercq · December 22nd, 2003, 02:30 PM

Do you have the shakes when only the XL1S is connected to the mixer? Mixers contain frame buffers ( and "de facto" contain a TBC function - jittery signals can't be mixed...)) in order to retime the incoming signals. The new timing can be maped on an external source (genlock), an independent internal reference, or can use one of the incoming signals as the reference timing. In the latter case, when there is a significant deviation in framerate between the mixed sources, the "buffer full" or the "buffer empty" flag, too often generates a drop or a repeat frame, which in consumer mixers can generate small shakes. Often horizontal and periodic.

Don Palomaki · December 23rd, 2003, 05:26 AM

Contact Videonics, ask them about the issue.

Note that the frame/field freeze option might cause jitter when used.

Does using a different input on the miser make a difference?

As I recall, the older MX1 mixer has an additional setup option that might effect image stability..

December 21st, 2003, 08:41 AM	#1
Patrick Lipawen New Boot Join Date: Apr 2003 Posts: 5	Mystery image shake Hello, We are using an XL1S and a cheaper Panasonic PVDV52 with an MXPro mixer - this is a broadcast setup for a closed-circuit TV program. The image from the XL1S shakes very slightly (but noticeably) when the camera is just sitting on the tripod. This occurs whether the stabilizer is on or off. There is nothing moving in front of the camera - just a still shot of a Bingo board or wall decorations. The image from the Panasonic (or from our other cheaper camera, a Canon ZR40) is perfectly still. We've tried exchanging cables, and switching inputs on the mixer, to no avail. Anyone know what might be causing the shake? Thanks for any help. Patrick Lipawen

December 21st, 2003, 04:39 PM	#7
Ken Tanaka Retired DV Info Net Almunus Join Date: Dec 2001 Location: Chicago, IL Posts: 6,943	To eliminate variables, try disconnecting the XL1s from the mixer and see if the image is stable direct to monitor. __________________ Lady X Films: A lady with a boring wardrobe...and a global mission. Hey, you don't have enough stuff! Buy with confidence from our sponsors. Hand-picked as the best in the business...Really! See some of my work one frame at a time: www.KenTanaka.com

December 22nd, 2003, 05:07 AM	#8
Don Palomaki Wrangler Join Date: Sep 2001 Location: Northern VA Posts: 4,489	How fast is the shake? How large is it. If about one line, it might be an issue in the mixer. __________________ dpalomaki@dspalomaki.com

December 22nd, 2003, 07:31 AM	#9
Jeff Donald Warden Join Date: Mar 2002 Location: Clearwater, FL Posts: 8,287	Most of the newer mixers use a frame synchronizer to mix the footage. However, the MXPro uses a TBC. Have you upgrade the mixer to use DV or are you using analog in? How long of a cable from the camera to the mixer? I think Ken, Andre and Don are on the right track. Do as Ken suggested and connect the camera directly to a monitor and check for any visible shake. If none is observed, then the mixer is the most likely cause. I would talk to Videonics and see what they suggest. __________________ Jeff Donald Carpe Diem Search DVinfo.net for quick answers \| Where to Buy? From the best in the business: DVinfo.net sponsors

December 23rd, 2003, 05:26 AM	#13
Don Palomaki Wrangler Join Date: Sep 2001 Location: Northern VA Posts: 4,489	Contact Videonics, ask them about the issue. Note that the frame/field freeze option might cause jitter when used. Does using a different input on the miser make a difference? As I recall, the older MX1 mixer has an additional setup option that might effect image stability.. __________________ dpalomaki@dspalomaki.com

December 21st, 2003, 02:48 PM	#2
Frank Granovski Outer Circle Join Date: May 2002 Location: Hope, BC Posts: 7,524	It's a stable tripod? Leave OIS disengaged. There could be slight shaking you cannot see, or perhaps the auto sensors are having trouble in lower light.

December 21st, 2003, 03:39 PM	#3
Patrick Lipawen New Boot Join Date: Apr 2003 Posts: 5	We have the Libec LS35. The shake occurs with or without the stabilizer. I'm fairly certain the ground is not shaking from construction or large objects being moved about. Also, we are broadcasting from a well-lit area. Any other ideas? Thanks in advance. Patrick

December 21st, 2003, 03:46 PM	#4
Andre De Clercq Major Player Join Date: Sep 2002 Location: Belgium Posts: 804	Are both cams connected to the mixer and a monitor, when you see the problem?

December 21st, 2003, 03:59 PM	#5
Andre De Clercq Major Player Join Date: Sep 2002 Location: Belgium Posts: 804	Is the shaking only horizontal? Is it periodic?

December 21st, 2003, 04:20 PM	#6
Patrick Lipawen New Boot Join Date: Apr 2003 Posts: 5	Yes, we connect both cameras to the mixer. From the mixer, one video out goes to a preview monitor, the other goes into a modulator for our closed-circuit system. The shaking with the XL1S is vertical, and it is constant. We can see it on the preview monitor, and everyone watching can see it when they turn on our house cable channel. It is only a slight movement, but I would like to get rid of it. Any suggestions? Patrick

December 22nd, 2003, 11:11 AM	#10
Patrick Lipawen New Boot Join Date: Apr 2003 Posts: 5	There is no shake when the XL1S is attached directly to the monitor. We didn't buy the digital upgrade, so we are using analog inputs. Our RCA cable is 6 ft long. I guess it is a mixer issue. I will go through our mixer settings and see if I can fix it. I'm not sure why the smaller miniDV cams don't have the same problem. Thanks for the replies! Patrick

December 22nd, 2003, 11:22 AM	#11
Rob Easler Major Player Join Date: Jan 2003 Location: Naperville, IL Posts: 219	Patrick, try to disengage the auto focus and see if it's still there. Sometimes there can be an effect that might resemble shaking if the auto focus is constantly seeking. It's probably not your issue but as none of us can see it, it's hard to judge and it's worth a shot.

December 22nd, 2003, 02:30 PM	#12
Andre De Clercq Major Player Join Date: Sep 2002 Location: Belgium Posts: 804	Do you have the shakes when only the XL1S is connected to the mixer? Mixers contain frame buffers ( and "de facto" contain a TBC function - jittery signals can't be mixed...)) in order to retime the incoming signals. The new timing can be maped on an external source (genlock), an independent internal reference, or can use one of the incoming signals as the reference timing. In the latter case, when there is a significant deviation in framerate between the mixed sources, the "buffer full" or the "buffer empty" flag, too often generates a drop or a repeat frame, which in consumer mixers can generate small shakes. Often horizontal and periodic.