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Camera tilt increases the fisheye effect why?

Discussion in 'Phantom 2 Vision Discussion' started by rfernandez, Feb 12, 2014.

  1. rfernandez

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    Ok, Perhaps some of the video and photo professional gurus can provide an logical answer to this question.
    Why is it that when i tilt my camera on the P2V downwards the fisheye effect increases exponentially as supposed to when I have the camera pointed straight out?

    see the link for the camera shots I took whole in Orlando ,FL at my time share resort

    See bellow!
     
  2. mr_3_0_5

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    Those links are not working for me
     
  3. rfernandez

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    let me repost them
     

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  4. Pull_Up

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    EDIT: These comments related to the original links you posted, which I could load no problem...

    I can see them. They all have the same amount of distortion, it's just that not seeing the horizon line disguises it with the clutter of all the other non-horizontal lines in the fully down shot. If you look at the top left and top right you of the one pointing down you can see a bit of horizon and that gives you an idea of the distortion.

    Also look at the long straight line on the grey roof on the right - it's not straight, but it's not quite as obvious because of all the other angles in the scene.
     
  5. rfernandez

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    So in other words when taking footage straight down or at an angle below the horizon make sure the horizon is not visible?
     
  6. ZonComGMZ

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    It's the same in all photos and videos. It is just more evident and enhanced when you see things toward the edges than in the middle. This is an easy thing to remove with just about any software.
     
  7. rfernandez

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    Final Cut Pro does a nice job of taking out the fisheye along with another plug in. I just noticed it more with this picture..

    Thanks,

    Richard
     
  8. gfredrone

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    You got a great sensor and lens. Looks pretty sharp edge to edge.
     
  9. rfernandez

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    yeah i kinda have been blessed with a good camera... lets hope it stays that way,,My next investment is to install a Rotorpixel gimbal. already have installed the switch in the back of the transmitter..
     
  10. CaptainChet

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    Simply put, that is the nature of a fisheye lens. It distorts verticals greater than horizontals and therefore point it up or down from level and you see the 'fisheye' effect in action. It can be corrected in post processing with a penalty of overall image quality.
     
  11. jimre

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    The curvature of the lens is obviously the same for every shot. I think you're just noticing it more on *high altitude* shots - and those happen to be the ones where you are pointing the camera more down. The higher the altitude, the larger the visible distances are in the image - and therefore the "warping" appears worse. The outer edges of the picture may be warped a few feet in a relatively close shot like your first one. But those same outer edges might be warping a quarter-mile distance in a long (high altitude) shot!
     
  12. iDrone

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    Vision's ultra-wide lens suffers/features (depends entirely upon your creative application & point of view) curvilinear barrel distortion. None of the image is flat, it just appears that way across the center of the lens. If you draw a semicircle on a piece of paper and view it from above, it looks like a half-circle. But if you look at the same drawing from the edge of the table it looks like a perfectly straight horizontal line.

    Place LEGO's along the semi-circle and view from above (Pull_Up c/o Aardman Animations, we need another video!) and it looks like the tops of a bunch of LEGO's standing in a half-circle. View from the edge of the table and the LEGO's all appear to be standing in a perfectly straight line, however The ones in the middle appear fat while those at the sides appear thin... from a distance you probably wouldn't even notice.


    Here's a still taken by Vision. The crosshatch chart's lines are perfectly straight & equidistant to each other, yet the distortion in the lens curves the lines except when they're dead center of the lens. If you don't want a curved horizon, tilt the camera so your horizon is centered vertically. Alternatively, you can remove the distortion using plug-in filters in many photo & video editing programs.

    I hope that helps,
    iDrone :ugeek:
     

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  13. LandYachtMedia

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    You can also minimize the effect if you shoot in 2.7k then bring the footage into the GoPro application and let it remove the distortion. You'll still get good sharpness in the final image.