Which camera would be best for motion tracking?

I don't really know any particular camera that is better specifically for motion tracking than another... as far as that goes most cameras are pretty much the same. Motion tracking and its quality is much more a function of the tracking software used... the the operator doing it.

If you are trying this and motion blur is causing tracking problems, then that issue is easily corrected by just shooting at a higher shutter speed. BUT... of course you run the risk of choppy/juddery-looking footage (the "Saving Private Ryan" or "Gladiator" effect), because the brain needs that motion blur to interpret footage as smooth.

I would suggest shooting progressive rather than interlaced, but of course that is more dictated by the "look" you are wanting for the project.

A 5D or 7D can certainly shoot 24p, and of course you can adjust your shutter speed on those cameras very easily. Again, though, remember that "normal" shutter speed (emulating a 180° shutter on a film camera) is "one over twice the frame rate"... therefore at 24p the "normal" shutter speed would be 1/48th. You can crank that up to eliminate the motion blur if that helps you track better... but again, the footage might look a bit too crisp and choppy.

T2

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Todd Terry
Creative Director
Fantastic Plastic Entertainment, Inc.
fantasticplastic.com

Ah that "bending" you a speaking of is probably due to a "rolling shutter effect"... which is especially seen on vertical lines during things like fast pans. I've never heard of anyone having tracking issues with a rolling shutter, but I think it's certainly possible. The problem with that and tracking is if you do get that bending, you'd want your tracked element to bend along with it to look real... otherwise it would give away the composite.

There are two kinds of camera shutters... "rolling" and "global." A rolling shutter basically "draws" the picture on from top to bottom of the frame, much like scan lines in an interlaced TV. The problem with that is, during fast moving shots (especially pans) the scene is in slightly different positions at the bottom and the top. It captures the frame at the top, but by the time the shutter reaches the bottom the shot is in a different position. When panning most noticeably vertical lines slant, because the tops and bottoms are in different positions. A GLOBAL shutter, unlike a rolling shutter, basically "snaps" all the frame at one time, eliminating those slanty and bendy lines.

You'll mostly find rolling shutters in CMOS sensor cameras such as DSLRs. Global shutters are more common in CCD cameras, such as "real" video cameras (not DSLRs). It may be that you can solve your issue by shooting with a camera with a global shutter, and discounting any with rolling shutters. There are exceptions, but to put it broadly that would mean not shooting with a DSLR and instead shooting with most any "regular" video camera.


[Jeremy Chopra] " I just need as crisp and clean an image devoid of motion blur"

Well as I said in my previous post, that's pretty easy... just crank up the shutter speed until you get crisp frames with no motion blur. 1/250th or higher should do it. Again though, keep in mind that you'll get juddery/stroby-looking video if there is fast motion in your scenes. Our brains and eyes need that motion blur to interpret it as smooth motion. Otherwise the too-crisp frames look very choppy when played in full motion.

T2

__________________________________
Todd Terry
Creative Director
Fantastic Plastic Entertainment, Inc.
fantasticplastic.com

Jeremy, you'll want the camera with the best resolution for motion tracking.

If you are good at it, then you will be frustrated by the line skipping resolution from DSLR cameras - stay away from it - unless you are using something like Nuke or Boujou, etc that can handle poor video.

Take a look at the Sony FS100 - and shoot at 50/60fps to eliminate 24p motion blur - the footage can then be retimed to 24p or whatever the delivery frame rate is.

At this budget the temporal resolution from the FS100 and its pixel pitch resolution should offer the best bet. Hope this helps.

http://wolfcrow.com/blog/ - Workflow information and support for filmmakers, photographers, audiographers and videographers.

Hi Jeremy,
there are some CMOS cameras that are "rolling shutter" free, like Canon XF300/305 and C300 (and probably the new ones from JVC). I'd choose one of these new designs instead of an old (but still good) CCD camera. The 4:2:2 50Mps recording data-rate will help to reduce the artifacts.

Best Regards,

Paolo.Castellano@ivs.it
http://www.ivsEdits.com
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