Flickering on a timelapse shot problem at DVinfo.net

Jamie Baughman · February 18th, 2008, 12:16 PM

Hi Folks,

I was doing some tests this weekend and came away with one weird shot.

Take a look at this link and let me know what you think:

http://jamiebaughman.com/street_corner.mov

You'll notice in the top area of the frame there's some flickering...almost like the light source from the topside of the camera is changing. I wasn't standing under a traffic light, street light, etc. Also, it was a clear blue sunny day. So a light source the size of a traffic light or street lamp wouldn't be powerful enough to make this happen. This is happening in the non-compressed file as well.

For comparison, here's another test I did against a clear blus sky the same day. No flickering here:

http://jamiebaughman.com/cloud_lapse.mov

Thanks in advance.

Eric Pascarelli · February 18th, 2008, 12:50 PM

Your overall exposure looks like it's changing. Did you have auto iris on?

When a dark car pulls in front of the camera, it looks like the camera is compensating by making the overall exposure brighter.

Auto iris is great for time lapse, but only if higher frequency events aren't going to affect it. I would use it for higher angle work - landscapes etc, and nothing where traffic movement would trigger it.

Same for auto shutter, of course.

Alexander Ibrahim · February 18th, 2008, 01:09 PM

I think the biggest culprit is auto iris.

I typed a bunch of stuff then noticed Eric Pascarelli beat me to it. He's right. He also spared you my novella- so thank him.

Other than that the only thing I have to add is that in addition to simply blocking light it looks as though you had some negative fill in there- but compared to the auto iris that's small potatoes.

Jamie Baughman · February 18th, 2008, 03:08 PM

Eric and Alexander,

Thanks much for your posts back. I was certain I was in auto iris, but since I'm still new to the camera it is entirely possible that I made such a bush league move.

Since the cloud scatter is not suffering from the same thing I'll bet that's what it was...

Thanks!

February 18th, 2008, 12:16 PM	#1
Jamie Baughman Regular Crew Join Date: Nov 2005 Location: San Francisco, CA Posts: 180	Flickering on a timelapse shot problem Hi Folks, I was doing some tests this weekend and came away with one weird shot. Take a look at this link and let me know what you think: http://jamiebaughman.com/street_corner.mov You'll notice in the top area of the frame there's some flickering...almost like the light source from the topside of the camera is changing. I wasn't standing under a traffic light, street light, etc. Also, it was a clear blue sunny day. So a light source the size of a traffic light or street lamp wouldn't be powerful enough to make this happen. This is happening in the non-compressed file as well. For comparison, here's another test I did against a clear blus sky the same day. No flickering here: http://jamiebaughman.com/cloud_lapse.mov Thanks in advance. __________________ Jamie Baughman

February 18th, 2008, 01:09 PM	#3
Alexander Ibrahim Major Player Join Date: Oct 2001 Location: Washington D.C. Metro Area Posts: 384	I think the biggest culprit is auto iris. I typed a bunch of stuff then noticed Eric Pascarelli beat me to it. He's right. He also spared you my novella- so thank him. Other than that the only thing I have to add is that in addition to simply blocking light it looks as though you had some negative fill in there- but compared to the auto iris that's small potatoes. __________________ Alexander Ibrahim http://www.alexanderibrahim.net

February 18th, 2008, 03:08 PM	#4
Jamie Baughman Regular Crew Join Date: Nov 2005 Location: San Francisco, CA Posts: 180	Eric and Alexander, Thanks much for your posts back. I was certain I was in auto iris, but since I'm still new to the camera it is entirely possible that I made such a bush league move. Since the cloud scatter is not suffering from the same thing I'll bet that's what it was... Thanks! __________________ Jamie Baughman

February 18th, 2008, 12:50 PM	#2
Eric Pascarelli Major Player Join Date: Nov 2007 Location: Los Angeles, CA Posts: 498	Your overall exposure looks like it's changing. Did you have auto iris on? When a dark car pulls in front of the camera, it looks like the camera is compensating by making the overall exposure brighter. Auto iris is great for time lapse, but only if higher frequency events aren't going to affect it. I would use it for higher angle work - landscapes etc, and nothing where traffic movement would trigger it. Same for auto shutter, of course.