Strange camera flash phenomenon at DVinfo.net

Vito DeFilippo · September 22nd, 2006, 08:13 PM

Hi all,

I was editing a wedding I shot a while back with a Z1. A tourist was taking a photo of the chapel. Three frames after the flash was a bizarre glitch in the frame that reminds me of some kind of electrical error. Anyone know what this is?

Shot with Z1 but in DV mode (4:3).

Frame 1 is normal. Frame 2 is camera flash. Frame three is strange glitch. Frame four is green afterglow of glitch.

Just curious,
Vito

Peter Jefferson · September 22nd, 2006, 10:18 PM

im surprised the vertical smearing didnt hit at the point of the flash... seems to me the Flash itself was set to a slow sync and as your camera shutter was prolly running a little slower than his flash sync, the nuance you see is the after effect of the blown out exopsure across CCD.
Also, by this behaviour and looking at your frames, its seems you were running the cameras iris in manual mode or if it was set to auto, more than likely the camera was too slow to respond to the exposure and got a litl wonky as it processed the exposure readings... which is why you get those strange frames as the cam fluctuates (albeit it slowly)
I honestly cant tell if u had the cam in manual or auto.. but this phenomnenon usually happens in auto mode, BUT can also happen in manual if ur shutter is too slow...

Vito DeFilippo · September 23rd, 2006, 07:18 AM

Hey Peter,

Yeah, I was in manual mode, but the alcove where the tourist was was very dark, so I had to boost the gain a fair amount. Shutter speed was normal 60i.

Never saw this before, and I've taped billions of camera flashes, as I'm sure you have...

Thanks,
Vito

Greg Boston · September 23rd, 2006, 09:21 AM

Wow, I thought you were going to post frames of small red matrix patterns which I saw when I edited my first wedding. It's the infrared autofocus operating on still cameras before the flash, which the video camera will see but the human eye will not.

-gb-

September 22nd, 2006, 08:13 PM	#1
Vito DeFilippo Trustee Join Date: Mar 2006 Location: Montreal, Quebec Posts: 1,585	Strange camera flash phenomenon Hi all, I was editing a wedding I shot a while back with a Z1. A tourist was taking a photo of the chapel. Three frames after the flash was a bizarre glitch in the frame that reminds me of some kind of electrical error. Anyone know what this is? Shot with Z1 but in DV mode (4:3). Frame 1 is normal. Frame 2 is camera flash. Frame three is strange glitch. Frame four is green afterglow of glitch. Just curious, Vito Attached Thumbnails __________________ . http://www.nosmallroles.com

September 23rd, 2006, 07:18 AM	#3
Vito DeFilippo Trustee Join Date: Mar 2006 Location: Montreal, Quebec Posts: 1,585	Hey Peter, Yeah, I was in manual mode, but the alcove where the tourist was was very dark, so I had to boost the gain a fair amount. Shutter speed was normal 60i. Never saw this before, and I've taped billions of camera flashes, as I'm sure you have... Thanks, Vito __________________ . http://www.nosmallroles.com

September 22nd, 2006, 10:18 PM	#2
Peter Jefferson Inner Circle Join Date: Apr 2003 Location: Aus Posts: 3,884	im surprised the vertical smearing didnt hit at the point of the flash... seems to me the Flash itself was set to a slow sync and as your camera shutter was prolly running a little slower than his flash sync, the nuance you see is the after effect of the blown out exopsure across CCD. Also, by this behaviour and looking at your frames, its seems you were running the cameras iris in manual mode or if it was set to auto, more than likely the camera was too slow to respond to the exposure and got a litl wonky as it processed the exposure readings... which is why you get those strange frames as the cam fluctuates (albeit it slowly) I honestly cant tell if u had the cam in manual or auto.. but this phenomnenon usually happens in auto mode, BUT can also happen in manual if ur shutter is too slow...

September 23rd, 2006, 09:21 AM	#4
Greg Boston Wrangler Join Date: Oct 2003 Location: DFW area, TX Posts: 6,117 Images: 1	Wow, I thought you were going to post frames of small red matrix patterns which I saw when I edited my first wedding. It's the infrared autofocus operating on still cameras before the flash, which the video camera will see but the human eye will not. -gb-