Help Motion Tracking a Scene

Hi everyone,

I’m working on a project for a short film and there is a scene that needs a CG grocery cart in it. I’m new to camera tracking and I’ve watched as many videos on the subject as I can find, but for some reason I cannot get this scene to track correctly. I’ve changed the model so many different times and tried both automatic trackers (detect features) and manual placement, but I still get unusable results. I would appreciate it if someone who has more knowledge and experience with the motion tracker could take a look at it and see what can be done. I want to learn from this, so if you find something I’m doing super incorrectly, please let me know.

Here’s the blend file:

Also, I hope the footage is already cached with the file, but if it isn’t, let me know and I can upload that too.

Thanks in advance!

Missing the footage. If you do have camera data like model and which lens was used, will help a lot.

Thank you for replying and letting me know!

Here’s the footage:

It’s already in an image sequence and the frame rate was 23.98. The camera was the Canon M50 with the standard EF-M 15-45mm lens. I’m not sure what the focal length was during the shot (I didn’t film it and I didn’t think to ask), but the aperture was set at f3.5, if you need that. If there is anything else I’m forgetting or didn’t say, just let me know again.

This is the best results I got with that footage, but orientation still bad. File: undis_cart_footage_track.blend Solve error: 1.23px
I tryed everything for this one, nothing worked. Canon UK official site doesn’t say if your camera use full sensor or it’s croped. So I changed sensor size for default 36mm. Yet since you do have a camera, I would shot again and take note of exact focal lenght, without zoom, trying to use with full sensor.


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Looking at the camera sensor, its APS-C. So not a full frame sensor.
This will already throw off the tracking if you start with full frame.
Also, the camera will crop video, as the sensor is a 3:2 ratio and not 16:9 for HD or 4K video. All this will define your tracking results.
Try to set this before a re-track and see if it will create a better track.

P.s. tracking can be a pain… :wink:

Some info on the camera:
PART 8 is very interesting regarding crops in the various lens and camera modes.


Thanks for giving it a go! I appreciate it.

Cool, thank you for the information! I will try re-tracking to see what I can get.

Yeah, I’m finding that out. :rofl:
Thanks again!