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Activity Forums Adobe After Effects How to zoom out of a video (eg: a stadium) and do a set extension around it?

  • How to zoom out of a video (eg: a stadium) and do a set extension around it?

    Posted by Mahesh Raj on February 26, 2017 at 5:46 am

    Hello Experts

    So grateful to use this platform to extend my knowledge in after effects,
    I have been committed to work on a project, below is the requirement of my work

    Real Scene:
    A drone shot. Starting from inside of a open football stadium the drone just flies out of stadium (like zooming out) revealing a high class city around the stadium while the cam keeps going up.

    Requirement:
    When the drone flies out of stadium the city around it which is getting revealed should be removed and instead of a high class city, they need something else like a desert for example.

    how do I make this possible, i tried few methods to mask out the stadium and place it in-between the dessert and composite it which is perfect, but the original footage which is already zooming out needs to continue zooming out while revealing the desert. Not able to do it.

    Any help will be greatly appreciated. Thank you all so much in advance.

    Sincerely
    Mahesh

    Thanks & DFTBA
    Mahesh Raj

    Mahesh Raj replied 9 years, 6 months ago 2 Members · 2 Replies
  • 2 Replies
  • Mike Sevigny

    February 26, 2017 at 2:34 pm

    hey Mahesh,
    What you’re describing is not an easy shot but is completely doable. It sounds like what you’re having trouble with is the animated camera.

    The fist thing you’ll need to do is track the camera (matchmove). There are a number of software packages that can accomplish this task, including After Effects. To launch AE’s Camera Tracker, select the clip in the timeline and click Animation>Track Camera. AE’s Camera Tracker is fantastic for 95% of shots you throw at it.

    In cases where the track is more complex, you will require a dedicated matchmoving package. For this, I recommend SynthEyes https://www.ssontech.com/ because of its ease of use, robust tools and price. When you track a camera in a matchmoving package, it helps to know what physical camera was used. Once you have the camera model, look it up on https://vfxcamdb.com/ and write down the ‘Sensor Size’ which is also known as ‘Filmback Size’. Together with the lens info, the sensor size will help track the camera accurately when using a dedicated matchmoving package like Syntheyes. Here are a few other matchmoving packages you can look into, PFTrack, 3D Equilizer, Boujou..

    Once the shot is tracked: You can either add a 2D image of the desert where the ground plane is and roto the stadium back on top of it. OR if the desert asset is 3D, you can take the tracked camera over to your 3D package and render the desert from the tracked camera’s perspective. When you import that 3D render into After Effects, it’ll line up perfectly with the footage so you can roto the stadium back on top of the 3D render and composite.

    It’s impossible to tell what the best method would be without seeing the shot. In some cases, using Mocha to track the ground and replace it with an image (of the desert) can also work without the need to track any camera. However, if there is parallax in your desert scene, you will want to use a 3D render instead of a 2D image.

    Note: You used the term ‘Zoom’ but I think what you mean is that the drone is flying out of the stadium into the sky revealing the stadium exterior as the shot gets wider. Animated ‘zoom’ means that the focal length of the camera is animated which is more complex to track.

    Hope this helps,
    Mike Sevigny
    https://www.torusmedialabs.com

  • Mahesh Raj

    February 26, 2017 at 3:54 pm

    Sincere thanks Mike.

    What you said is correct, what I meant was the drone is flying out of the stadium into the sky revealing the stadium exterior as the shot gets wider.

    I will go ahead I try it with after effects now, besides do we have any tutorial on these kinda set extensions anywhere online? thought It would be so much easier to learn these advanced techniques.

    Thanks a lot again.

    Thanks & DFTBA
    Mahesh Raj

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