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Different Focal Length and Different Rotation of Camera in Photogrammetry - FORBIDDEN (!?)

Jonathan85
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Jonathan85 polycounter lvl 9
Hello, i have been using some old version of agisoft metashape, now im using some newer but still older version (than the current one is). Its 1.5.5.
With this "newer but still old version" i got new error messages pop up here there, these didnt pop up EVER in previous versions.


They say:
Warning! The following problems can lead to suboptimal results:
- Images with variable zoom are added to the project. It is strongly recommended to avoid zooming as much as possible.
Happens when i upload images with "zoom" (or different Focal lenght in other words).
I have ALWAYS done this and never had this warning pop up before... DOes using different Focal Lenght ("zoom") really negativelly affect the final quality of the scan...? I have never noticed that...? IS that true? Or is that true only with never versions of metashape and older could handle it and newer give worse results? Or is it in all photogrammetry software that using different focal length leads to bad results...? I would swear i did some tests with this back in 2015 (or whatever) when i started with 3D scanning and never saw bad results...?
Is it worse? How much worse is it...? Zoom is sometimes necessary i feel... Should i really avoid it like the plague?


And another one:
Warning! The following problems can lead to suboptimal results:
- Images with different orientation are added to the project. It is strongly recommended to disable auto rotation in the camera or photo processing software.

Again...? Does different rotation matter? (in this example i scanned some leaf and few photos had the same leaf, the same side of the leaf, just aprx. 90 degree rotated...
I have dont this before i think and no problem. No it gives me this warning and also the point cloud looks weird... (like wrong, "normals" flipped).


So how is?
1) Is using different Focal length really THAT BAD? Should i avoid it at all cost...? (any pictures of tests for this...?)
2) Is using different rotation (mainly switching holding the camera verticaly or horizonatally; but even rotations like 30% only for example)... Is this also BAD...? How MUCH bad... should be avoided at ALL COSTS...?

(camera i use: Nikon D3100)

Replies

  • gnoop
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    gnoop sublime tool
    it's really THAT BAD  in both cases.  As well as shooting  from same standing point and rotating your self  around without true parallax .
    It's just before they told you nothing and you just got crappy result.    Reality capture for comparison wouldn't tell you anything but  you would be getting  a mess of a  point cloud
  • Jonathan85
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    Jonathan85 polycounter lvl 9
    Hello

    Well... i have used zoom before so as rotating the camera by 90 degrees and got good results, i think... no point mess, nothing... just general a little bit "blobiness" of the mesh, but thats for all scans i think (unless you are using like high end full frame cameras)...
    Granted i didnt use the zoom (chnage the focal length) that often but still i did it a plenty of times... didnt really noticed any problems...

    what problems would it cause please? Liekthat the point wouldnt allign at all...? Or that the mesh/dense point cloud would be really "blobby"?


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