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iRiS Stereoscopic Base and Disparity Calculator – 1.1.0 Update – Introducing the Roundness Factor

The Stereoscopic Base and Disparity Calculator 1.1.0 for the Android OS has just been updated and introduces a new base calculation measured around the perceived on-screen Roundness or depth of an image.

The new option allows the user to either :

  • Calculate the camera base separation using a predetermined target parallax amount
  • Calculate the camera base separation to a “Roundness Factor” of 1.0.

The Roundness Factor represents the factorial difference in depth between the photographed scene and the resultant projected 3D scene.

It is generally referred as a factor because ideally one would want to capture and project the same depth representation of photographed object, thus having a factor of 1.0.    IE: Physical scene depth/perceived 3D on-screen depth.

If the Roundness Factor is less than 1.0 then for example a round sphere will appear flat and compressed. It will have lost is dimensionality.

If the Roundness Factor is greater than 1.0 then the same sphere will appear stretched or extruded on the Z depth plane.

Consider dimensionality in filming the close-up of someones strong angular face. Captured with perfect roundness the 3D on-screen projected face will feel volumetric and proportionately correct. If the “Roundness Factor” starts getting too high the persons head and nose will begin to feel stretched toward the viewer, which is not such a flattering look.  In this sense it is better to err on the side of a factor less than 1.0.

The effect of Roundness is related very closely to Lens selection. A longer focal length lens will have a much greater impact on roundness and Parallax as the base separation in altered. On a 75mm Lens it takes only small changes in Base distance to make quite large differences in background parallax and therefor depth.   Additionally sensor size is quite an important factor to consider as the resulting 35mm Lens equivalents could be a lot higher than you think.

As always it is recommended to test Lens/Sensor configs as much as possible before entering any project.


One Response to “iRiS Stereoscopic Base and Disparity Calculator – 1.1.0 Update – Introducing the Roundness Factor”

  1. Hans says:

    Dear Adrian,

    my IRIS S3D calculator dosn’t work anymore since I got Android 4.0.3 on my HTC EVO3D. I cannot start the app. I need it almost daily! What is to do?

    Hope to hear from you soon!


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