Help!White flash in video? at DVinfo.net

Daniel Dayani · March 4th, 2011, 12:34 PM

Hey guys so far this has only happened 3 times but when i am recording in a semi-dark room and someone takes a photograph( atleast thats what i THINK it is), about the top 1/3 of my screen goes absolutely white. It is a really quick flash of white light that although its quick, is definitely noticeable. the pictures i attached show a pretty good example of whats happening. Is this simply the camera's white balance trying to adjust to the flash of somebody else's photo or what. I hope this is'nt a defect of my camera!!! Thanks!

Lance Watts · March 4th, 2011, 01:34 PM

This happens on all cameras with CMOS sensors and a rolling shutter system and, as far as I know, there is no way to avoid this. When you're shooting video, the shutter "rolls" across the sensor, exposing each frame. In other words the top and bottom of each frame is not being exposed simultaneously. There is an tiny lag as the shutter rolls across each frame. This is also what causes "jello" in fast pans.

Anyway, when someone fires off a flash, the portion of the frame that is currently being exposed when the flash goes off will be overexposed.

Jon Fairhurst · March 4th, 2011, 02:01 PM

That is due to the CMOS sensor in the camera. They all do that. CMOS sensors have a rolling shutter, meaning that each line's exposure starts slightly later than that of the previous line.

If you shoot concerts and fashion shows where there are lots of strobes, you're better off with a 3CCD camera.

Daniel Dayani · March 5th, 2011, 04:02 PM

thanks guys, relieved me even though thats kinda bad news since i usually shoot small little shows.cheers

Lance Watts · March 9th, 2011, 02:09 PM

If you were shooting with a 3ccd camera, the entire frame would be overexposed, rather than just part of the frame. Either way, flashes are annoying. If you're shooting any sort of event where people are shooting with flashes, it's just something you have to live with. It used to drive me crazy but I hardly even notice it anymore.

March 4th, 2011, 12:34 PM	#1
Daniel Dayani Regular Crew Join Date: Nov 2010 Location: Topanga, CA, USA Posts: 39	Help!White flash in video? Hey guys so far this has only happened 3 times but when i am recording in a semi-dark room and someone takes a photograph( atleast thats what i THINK it is), about the top 1/3 of my screen goes absolutely white. It is a really quick flash of white light that although its quick, is definitely noticeable. the pictures i attached show a pretty good example of whats happening. Is this simply the camera's white balance trying to adjust to the flash of somebody else's photo or what. I hope this is'nt a defect of my camera!!! Thanks! Attached Thumbnails

March 4th, 2011, 01:34 PM	#2
Lance Watts Regular Crew Join Date: Oct 2009 Location: Portland, OR Posts: 69	Re: Help!White flash in video? This happens on all cameras with CMOS sensors and a rolling shutter system and, as far as I know, there is no way to avoid this. When you're shooting video, the shutter "rolls" across the sensor, exposing each frame. In other words the top and bottom of each frame is not being exposed simultaneously. There is an tiny lag as the shutter rolls across each frame. This is also what causes "jello" in fast pans. Anyway, when someone fires off a flash, the portion of the frame that is currently being exposed when the flash goes off will be overexposed.

March 4th, 2011, 02:01 PM	#3
Jon Fairhurst Inner Circle Join Date: May 2006 Location: Camas, WA, USA Posts: 5,513	Re: Help!White flash in video? That is due to the CMOS sensor in the camera. They all do that. CMOS sensors have a rolling shutter, meaning that each line's exposure starts slightly later than that of the previous line. If you shoot concerts and fashion shows where there are lots of strobes, you're better off with a 3CCD camera. __________________ Jon Fairhurst

March 5th, 2011, 04:02 PM	#4
Daniel Dayani Regular Crew Join Date: Nov 2010 Location: Topanga, CA, USA Posts: 39	Re: Help!White flash in video? thanks guys, relieved me even though thats kinda bad news since i usually shoot small little shows.cheers

March 9th, 2011, 02:09 PM	#5
Lance Watts Regular Crew Join Date: Oct 2009 Location: Portland, OR Posts: 69	Re: Help!White flash in video? If you were shooting with a 3ccd camera, the entire frame would be overexposed, rather than just part of the frame. Either way, flashes are annoying. If you're shooting any sort of event where people are shooting with flashes, it's just something you have to live with. It used to drive me crazy but I hardly even notice it anymore.