Camera projection problem : the projected image is weirdly distorded

[metatoma]

Hello maya peeps,

I'm facing a problem that is driving me nuts.

Here is the plot :

1) i modelled a scene, placed a camera, found an angle and focal lens i liked

2) did a quick render

3) i finalised the image in photoshop where i added details

4) i reprojected the painting from a duplicated camera, identical to the one that been used to make the render

5) result : the projected image comes out wrong

I've tried to lower values from my focal lenght, lens distortion, it does affect the projection but i can't make it fit to the geometry.

I've matched the camera projection attributes (fit type and fit fill) to the two cameras in my scene as well. 

Please find screenshots below, that will help illustrate my problem.

result

What am I missing there ? Any idea ?

[metatoma]

couldn't get my head around it, so i've started the whole thing again.

this time, i tweaked the camera settings only on the render_cam rather than distord the projection one and paint over it.