Frame-split camera flash? Help? at DVinfo.net

Jeff Kolada · October 9th, 2007, 03:30 PM

I am shooting 1080p with my V1u onto sony blue tapes. I don't know if this is a tape problem or a general HDV problem, so please help me out.

Below are three frames from some skating footage I was shooting. Can anyone tell me what is going wrong? I am not using HDV tapes, but i've heard that the sony blues work just as well.
Thanks,
-Jeff

http://i24.photobucket.com/albums/c4.../hd_fu_fr3.jpg

http://i24.photobucket.com/albums/c4.../hd_fu_fr2.jpg

http://i24.photobucket.com/albums/c4.../hd_fu_fr1.jpg

Victor Wilcox · October 9th, 2007, 04:14 PM

Is this during a photo flash? If so, it's a know issue with HDV. The flash screws up the compression/GOP resulting in images similar to those posted.

Bob Hart · October 9th, 2007, 05:46 PM

I have had flash on HDV at music gigs which looked "normal" but I was using the slow shutter speed of 1/50 sec. I do not observe much motion blur in the grabs which suggests to me a higher shutter speed of say 1/250th or higher may have been in use. Only guessing though so don't pay too much heed to my comment. There is an interesting artifact around the top of that tripod or light stand. Was that a flash source? If there was no flash, was your camera anywhere near an operating mobile telephone (cellphone)?

Vaughan Wood · October 9th, 2007, 06:38 PM

This is exactly the "rolling shutter" effect you get with photgrapher's flashes and/or very fast movement.

To do with CMOS chips reading its info from top to bottom and you wont get it with CCD's.

Nothing to do with your tapes.

Check it out yourself by setting the camera up in a low light situation then get out your still camera and pretend your a photgrapher. Then view the tape back frame by frame over the flashes! (Worse in slow motion).

The main reason I bought an FX 1 for weddings and leave my FX 7 in the car as back up.

Cheers Vaughan

K.C. Luke · October 9th, 2007, 06:49 PM

Have notice on V1E as well. So any tips or setting up shutter speed of 1/100 sec above?

Stephen Armour · October 10th, 2007, 01:17 PM

Quote:

Originally Posted by K.C. Luke

Have notice on V1E as well. So any tips or setting up shutter speed of 1/100 sec above?

Nothing you can do about it, basically. It's a design prob with how Sony does CMOS. Try shooting lightning and you'll see it as well.

Dave Blackhurst · October 10th, 2007, 02:40 PM

IMO shutter speed won't really resolve the "problem" - it's strictly a matter of how the imaging chip is "read", which is not all at once - you'll notice from the pictures posted that flashes result in horizontal "bands", some of which show the exact moment of the flash, while adjacent bands show the moment before or after - we're talking milliseconds here - extremely small slices of time. I've had shots while experimenting where the chip captured the whole frame "lit", others show the banding... it's a function of the synchronization with the event...

At some point, CMOS will probably be capable of processing complete "frames" in one "chunk", but for now it seems that for all the CMOS advantages, this is the one fly in the ointment... and all CMOS based cams, not just Sony, exhibit the same behavior.

I've managed to work around it, and even with the flaws, it's better than how some individual frames looked when a flash went off with my SD cams...

K.C. Luke · October 10th, 2007, 06:09 PM

Quote:

Originally Posted by Stephen Armour

Nothing you can do about it, basically. It's a design prob with how Sony does CMOS. Try shooting lightning and you'll see it as well.

Thanks. coming projects will see how was it on more lights

Douglas Spotted Eagle · October 10th, 2007, 06:21 PM

Quote:

Nothing you can do about it, basically. It's a design prob with how Sony does CMOS. Try shooting lightning and you'll see it as well.

It's how low cost/small CMOS functions. Not a Sony, Canon, JVC, Panasonic, or anyone else does CMOS.

John Bosco Jr. · October 11th, 2007, 12:13 AM

Quote:

Originally Posted by Dave Blackhurst

At some point, CMOS will probably be capable of processing complete "frames" in one "chunk", but for now it seems that for all the CMOS advantages, this is the one fly in the ointment... and all CMOS based cams, not just Sony, exhibit the same behavior.

Be careful when you say "all CMOS based cams." I agree that the low cost ones do but not all. Some of the higher end CMOS cams employ a global shutter system instead of a rolling one.

Douglas Spotted Eagle · October 11th, 2007, 07:07 AM

Exactly. RED, as one example, uses a CMOS sensor as well.

Ron Little · October 11th, 2007, 07:27 AM

I shoot a lot of weddings. When I first used my V1 and saw all the rolling shutter effects from photog flash I thought the footage was going to be crap/useless.

The first time I delivered a wedding I cut as many flashes out as possible and hoped they would not notice/complain. As it turned out they not only did not see the rolling shutter but loved the look of the V1 footage.

Now I do not worry about the flash it is part of the event I have never had any client say anything about the effect. I was all prepared to explain the new technology, CMOS, rolling shutter, photog flash, and no one ever asked. So I just let it go.

If it really bothers you, you could enhance the flash and white out that frame. Or darken or lighten the half that is effected to make it not so noticeable. But for events I just don’t see the need.

Ethan Cooper · October 11th, 2007, 09:56 AM

The rolling shutter flash effect is a problem, but I've found that most consumers don't even know it's there. It's acceptable for flash photography, but I'd guess it pretty much f's up a lightning shot.
I've seen it all over the news recently. I think it was on some footage of Britney Spears with the Paparazzi clicking happily away and this footage was on CNN, FOX News, ABC, NBC, all the major networks. They didn't seem to have a problem using it. That's not saying much though as they routinely use video footage shot with cell phones.
It's not just a Sony problem as someone said before. Even the Red One suffers from the dreaded CMOS rolling shutter problem... and sheer... CMOS technology isn't all grown up quite yet.

*EDIT*
It helps to read the entire thread. It would appear that several people have already pointed out that RED uses a rolling shutter too. Oops.

Bob Hart · October 11th, 2007, 10:17 AM

Fopp !! The sound of my foot coming out of mouth. I misread the title of this thread FX1 for FX7 so my comment above has absolutely no relevance whatever. Sorry about the misinfo.

Jeff Kolada · October 11th, 2007, 12:35 PM

thanks alot all. Looks like I'm gonna have to play around with it a little bit and see if i can do anything to reduce it, or just cut some footage. As a first post in this forum, I am really liking the kind of feedback I am getting. Thanks to everyone who commented.

October 9th, 2007, 03:30 PM	#1
Jeff Kolada Regular Crew Join Date: Oct 2007 Location: Los Angeles, CA Posts: 78	Frame-split camera flash? Help? I am shooting 1080p with my V1u onto sony blue tapes. I don't know if this is a tape problem or a general HDV problem, so please help me out. Below are three frames from some skating footage I was shooting. Can anyone tell me what is going wrong? I am not using HDV tapes, but i've heard that the sony blues work just as well. Thanks, -Jeff http://i24.photobucket.com/albums/c4.../hd_fu_fr3.jpg http://i24.photobucket.com/albums/c4.../hd_fu_fr2.jpg http://i24.photobucket.com/albums/c4.../hd_fu_fr1.jpg Last edited by Jeff Kolada; October 9th, 2007 at 03:31 PM. Reason: fix picture links

October 9th, 2007, 04:14 PM	#2
Victor Wilcox Major Player Join Date: Sep 2006 Location: Iron Horse Guest Ranch, Waller County, TX Posts: 340	Is this during a photo flash? If so, it's a know issue with HDV. The flash screws up the compression/GOP resulting in images similar to those posted. __________________ Vic Wilcox, http://wilcoxvideoproductions.com/Default.aspx Sony FDR-AX100, DJI Phantom 4 Pro, GoPro Hero 8 Blk, Vegas Pro 15, DaVinci Resolve 18

October 9th, 2007, 05:46 PM	#3
Bob Hart Inner Circle Join Date: Dec 2003 Location: PERTH. W.A. AUSTRALIA. Posts: 4,477	I have had flash on HDV at music gigs which looked "normal" but I was using the slow shutter speed of 1/50 sec. I do not observe much motion blur in the grabs which suggests to me a higher shutter speed of say 1/250th or higher may have been in use. Only guessing though so don't pay too much heed to my comment. There is an interesting artifact around the top of that tripod or light stand. Was that a flash source? If there was no flash, was your camera anywhere near an operating mobile telephone (cellphone)? Last edited by Bob Hart; October 9th, 2007 at 05:54 PM. Reason: added text.

October 9th, 2007, 06:49 PM	#5
K.C. Luke Regular Crew Join Date: Jul 2007 Location: Singapore Posts: 173	Have notice on V1E as well. So any tips or setting up shutter speed of 1/100 sec above? __________________ Edit on Adobe Creative Suite Production Premium CS5 Mac 64BIT

October 11th, 2007, 07:07 AM	#11
Douglas Spotted Eagle VASST Join Date: Jan 2004 Location: Stockton, UT Posts: 5,648	Exactly. RED, as one example, uses a CMOS sensor as well. __________________ Douglas Spotted Eagle/Spot Author, producer, composer Certified Sony Vegas Trainer http://www.vasst.com

October 9th, 2007, 06:38 PM	#4
Vaughan Wood Major Player Join Date: Dec 2006 Location: Melbourne Australia Posts: 278	This is exactly the "rolling shutter" effect you get with photgrapher's flashes and/or very fast movement. To do with CMOS chips reading its info from top to bottom and you wont get it with CCD's. Nothing to do with your tapes. Check it out yourself by setting the camera up in a low light situation then get out your still camera and pretend your a photgrapher. Then view the tape back frame by frame over the flashes! (Worse in slow motion). The main reason I bought an FX 1 for weddings and leave my FX 7 in the car as back up. Cheers Vaughan

October 10th, 2007, 02:40 PM	#7
Dave Blackhurst Inner Circle Join Date: Feb 2007 Location: Apple Valley CA Posts: 4,874	IMO shutter speed won't really resolve the "problem" - it's strictly a matter of how the imaging chip is "read", which is not all at once - you'll notice from the pictures posted that flashes result in horizontal "bands", some of which show the exact moment of the flash, while adjacent bands show the moment before or after - we're talking milliseconds here - extremely small slices of time. I've had shots while experimenting where the chip captured the whole frame "lit", others show the banding... it's a function of the synchronization with the event... At some point, CMOS will probably be capable of processing complete "frames" in one "chunk", but for now it seems that for all the CMOS advantages, this is the one fly in the ointment... and all CMOS based cams, not just Sony, exhibit the same behavior. I've managed to work around it, and even with the flaws, it's better than how some individual frames looked when a flash went off with my SD cams...

October 11th, 2007, 07:27 AM	#12
Ron Little Major Player Join Date: Feb 2003 Location: Pensacola Fl. Posts: 627	I shoot a lot of weddings. When I first used my V1 and saw all the rolling shutter effects from photog flash I thought the footage was going to be crap/useless. The first time I delivered a wedding I cut as many flashes out as possible and hoped they would not notice/complain. As it turned out they not only did not see the rolling shutter but loved the look of the V1 footage. Now I do not worry about the flash it is part of the event I have never had any client say anything about the effect. I was all prepared to explain the new technology, CMOS, rolling shutter, photog flash, and no one ever asked. So I just let it go. If it really bothers you, you could enhance the flash and white out that frame. Or darken or lighten the half that is effected to make it not so noticeable. But for events I just don’t see the need.

October 11th, 2007, 09:56 AM	#13
Ethan Cooper Trustee Join Date: Dec 2003 Location: Houma, La. Posts: 1,400 Images: 5	The rolling shutter flash effect is a problem, but I've found that most consumers don't even know it's there. It's acceptable for flash photography, but I'd guess it pretty much f's up a lightning shot. I've seen it all over the news recently. I think it was on some footage of Britney Spears with the Paparazzi clicking happily away and this footage was on CNN, FOX News, ABC, NBC, all the major networks. They didn't seem to have a problem using it. That's not saying much though as they routinely use video footage shot with cell phones. It's not just a Sony problem as someone said before. Even the Red One suffers from the dreaded CMOS rolling shutter problem... and sheer... CMOS technology isn't all grown up quite yet. EDIT It helps to read the entire thread. It would appear that several people have already pointed out that RED uses a rolling shutter too. Oops. __________________ ∅ -Ethan Cooper

October 11th, 2007, 10:17 AM	#14
Bob Hart Inner Circle Join Date: Dec 2003 Location: PERTH. W.A. AUSTRALIA. Posts: 4,477	Fopp !! The sound of my foot coming out of mouth. I misread the title of this thread FX1 for FX7 so my comment above has absolutely no relevance whatever. Sorry about the misinfo.

October 11th, 2007, 12:35 PM	#15
Jeff Kolada Regular Crew Join Date: Oct 2007 Location: Los Angeles, CA Posts: 78	thanks alot all. Looks like I'm gonna have to play around with it a little bit and see if i can do anything to reduce it, or just cut some footage. As a first post in this forum, I am really liking the kind of feedback I am getting. Thanks to everyone who commented.