Maximum camera movement for match-moving at DVinfo.net

Vincent Mesman · February 6th, 2008, 01:04 PM

Hi,

I'm trying to find out what would be the maximum camera movement with the PMW-EX1 without generating too much errors during the match-moving process (with SynthEyes).

The EX1 does have rolling shutter problems that will frustrate a good 3D solve when there is too much camera movement.

I want to use the EX1 in hand-held situations with relative slow movements: pans and/or truck-in/out, let's say a 90 degrees pan per 3 seconds with a +/- 30 degrees horizontal pov and at least 1/200s shutter to minimize motionblur (in my experience it's too difficult to keep the trackers on their path with a 1/60s or 1/50s shutter).

Paul Kellett · February 6th, 2008, 01:07 PM

Nothing to worry about.

Eric Pascarelli · February 6th, 2008, 01:22 PM

I've had boujou reject some shots from my EX1 with excessive movement.

I agree that you will do better with a tighter shutter.

But it's hard for the software to reconcile that the bottom of frame is shot 1/60 second after the top of the frame. Hopefully this will be written into future versions of some tracking software. In fact this rolling shutter delay, when accounted for by software, might actually improve tracking by adding a temporal component to each still frame!

One thing I might try on a difficult track is to crop the image - use only 1/3 of the image in a horizontal slice for your track. Use the busiest, most detailed part of your image. This should reduce the 2D spatial error from the rolling shutter by 1/3.

February 6th, 2008, 01:04 PM	#1
Vincent Mesman Regular Crew Join Date: May 2007 Location: Amsterdam, The Netherlands, Europe Posts: 31	Maximum camera movement for match-moving Hi, I'm trying to find out what would be the maximum camera movement with the PMW-EX1 without generating too much errors during the match-moving process (with SynthEyes). The EX1 does have rolling shutter problems that will frustrate a good 3D solve when there is too much camera movement. I want to use the EX1 in hand-held situations with relative slow movements: pans and/or truck-in/out, let's say a 90 degrees pan per 3 seconds with a +/- 30 degrees horizontal pov and at least 1/200s shutter to minimize motionblur (in my experience it's too difficult to keep the trackers on their path with a 1/60s or 1/50s shutter).

February 6th, 2008, 01:07 PM	#2
Paul Kellett Trustee Join Date: Nov 2007 Location: Bristol UK Posts: 1,273	Nothing to worry about. __________________ Round 2 GH5,FZ2000

February 6th, 2008, 01:22 PM	#3
Eric Pascarelli Major Player Join Date: Nov 2007 Location: Los Angeles, CA Posts: 498	I've had boujou reject some shots from my EX1 with excessive movement. I agree that you will do better with a tighter shutter. But it's hard for the software to reconcile that the bottom of frame is shot 1/60 second after the top of the frame. Hopefully this will be written into future versions of some tracking software. In fact this rolling shutter delay, when accounted for by software, might actually improve tracking by adding a temporal component to each still frame! One thing I might try on a difficult track is to crop the image - use only 1/3 of the image in a horizontal slice for your track. Use the busiest, most detailed part of your image. This should reduce the 2D spatial error from the rolling shutter by 1/3.