Stutter in a viewfinder at 24p? at DVinfo.net

Bart Walczak · July 8th, 2006, 11:21 AM

Hello everyone,

We have been using our JVC HD101E to a great effect in HD-SD50p mode, but we also wanted to shoot in 720p24. When I switched to 24p mode, we encountered such strange phenomenon:

The picture in both Viewfinder and LCD stutters and updates like every 0.5 second or so. It is pretty hard to work with. The recording is ok, both on the tape, and on Firestore drive.

Has any of you encountered anything similar?

Thanks for any help.

David Jimerson · July 8th, 2006, 12:02 PM

A pronounced stutter in the viewfinder -- particularly the LCD -- is common in 24p cameras. As you've seen, the footage is OK.

Bart Walczak · July 9th, 2006, 02:38 AM

Thanks for the info. Is there any reason for this?

Stephan Ahonen · July 9th, 2006, 03:06 PM

The refresh rate of the LCD is probably fixed at 60hz, causing pulldown to occur whenever 24p material has to be displayed.

David Jimerson · July 9th, 2006, 08:22 PM

Pulldown itself doesn't cause it; you watch movies on TV every day with pulldown and they don't stutter. But I suspect it does have to do with a poor refresh rate.

Earl Thurston · July 9th, 2006, 08:36 PM

Quote:

Originally Posted by Bart Walczak

...wanted to shoot in 720p24. When I switched to 24p mode, we encountered such strange phenomenon:
The picture in both Viewfinder and LCD stutters and updates like every 0.5 second or so. It is pretty hard to work with.

Actually, Bart, this doesn't sound right. Do you mean the image stutters while filming, or upon playback?

If you mean during filming, something is wrong. The camera section actually updates at 48 frames per second (twice as fast as 24fps), so there should be no noticable strobing while viewing a live image, especially a stutter as severe as 0.5 seconds.

David Jimerson · July 9th, 2006, 08:39 PM

I've seen it too, in the HD100. Didn't strike me as anything unusual, but you think it is?

Earl Thurston · July 10th, 2006, 08:45 AM

Quote:

Originally Posted by David Jimerson

Didn't strike me as anything unusual, but you think it is?

I'd be concerned. I haven't seen it in mine, but if it happens I'd consider taking it in.

Tim Dashwood · July 10th, 2006, 08:53 AM

This may be normal in 24P mode on the HD101E.
I know that when I put the HD100U in 25P mode the LCD refresh rate is a little "weird" and the image is squeezed into a downconverted PAL mode. Maybe the opposite happens on European models in 24P and 30P mode because the default refresh rate for the LCD is set to 50Hz instead of 60Hz? Is this a viable theory?

Either way, the HDV end result should be unaffected.

July 8th, 2006, 11:21 AM	#1
Bart Walczak Major Player Join Date: Apr 2006 Location: Warsaw/Poland Posts: 716	Stutter in a viewfinder at 24p? Hello everyone, We have been using our JVC HD101E to a great effect in HD-SD50p mode, but we also wanted to shoot in 720p24. When I switched to 24p mode, we encountered such strange phenomenon: The picture in both Viewfinder and LCD stutters and updates like every 0.5 second or so. It is pretty hard to work with. The recording is ok, both on the tape, and on Firestore drive. Has any of you encountered anything similar? Thanks for any help.

July 8th, 2006, 12:02 PM	#2
David Jimerson Jubal 28 Join Date: Mar 2005 Location: Wilmington, NC Posts: 872	A pronounced stutter in the viewfinder -- particularly the LCD -- is common in 24p cameras. As you've seen, the footage is OK. __________________ www.wrightsvillebeachstudios.com

July 9th, 2006, 08:22 PM	#5
David Jimerson Jubal 28 Join Date: Mar 2005 Location: Wilmington, NC Posts: 872	Pulldown itself doesn't cause it; you watch movies on TV every day with pulldown and they don't stutter. But I suspect it does have to do with a poor refresh rate. __________________ www.wrightsvillebeachstudios.com

July 9th, 2006, 08:39 PM	#7
David Jimerson Jubal 28 Join Date: Mar 2005 Location: Wilmington, NC Posts: 872	I've seen it too, in the HD100. Didn't strike me as anything unusual, but you think it is? __________________ www.wrightsvillebeachstudios.com

July 10th, 2006, 08:53 AM	#9
Tim Dashwood Wrangler Join Date: Aug 2005 Location: Toronto, ON, Canada Posts: 3,637	This may be normal in 24P mode on the HD101E. I know that when I put the HD100U in 25P mode the LCD refresh rate is a little "weird" and the image is squeezed into a downconverted PAL mode. Maybe the opposite happens on European models in 24P and 30P mode because the default refresh rate for the LCD is set to 50Hz instead of 60Hz? Is this a viable theory? Either way, the HDV end result should be unaffected. __________________ Tim Dashwood

July 9th, 2006, 02:38 AM	#3
Bart Walczak Major Player Join Date: Apr 2006 Location: Warsaw/Poland Posts: 716	Thanks for the info. Is there any reason for this?

July 9th, 2006, 03:06 PM	#4
Stephan Ahonen Major Player Join Date: Apr 2005 Posts: 512	The refresh rate of the LCD is probably fixed at 60hz, causing pulldown to occur whenever 24p material has to be displayed.