"Gone Nuts 3D" Takeaway #5: Matte Box Beware

Takeaway #5:  Matte Box Beware

The Day Marking My Compulsion to Obsessively Check the Split Beam and Left Camera

Sitting down in our editing bay, an aptly named Booth 3, I assembled the right and left clips from our Gone Nuts 3D shoot into stereosequences.  I synchronized the clips and quickly checked for any other potential problems when I noticed a giant black shadow in the lower left corner of the left image and the tops of both the left and the right:

Raw Framepacked Clip 1095

I have framepacked the clips and highlighted the problems for ease of comparison.

What are those gigantic black shadows?  Only the Shadow knows...

Examining the field monitors on The Warehouse 3D/Chris Eller

Turns out that those shadows are from none other than our 3D rig's matte box.  In our split beam configuration, the left camera hangs underslung shooting into a mirror.  We filmed on a gorgeous September day which worked well for lighting our set but which worked poorly for seeing anything aside from glares in our field monitors.  This ruled out utilizing the field monitors to compare for side by side continuity. The scene was clear in the right camera, located on top of the rig so we never thought to check that the left camera was clear.  Oops.  

Close-up of the left camera and matte box/Chris Eller

As I sat and stared at the clips, each left clip filmed from this camera position had the notorious lower left shadow.  We had only filmed three takes of one shot from this position.  Thankfully, this meant I only faced the shadow dilemma once.  However, this shot was essential to our story as it was the moment where Arnold confronts and accuses the children of hitting him in the head with the wiffle ball.  

Fixing the top of the images posed no problem at all.  When I fixed the vertical disparity and roll, I scaled the images up in order to align them together.  In doing so, the top parts of the image were cropped out of sight.  Now, just the pesky bottom problem remained.

I tried lightening the shadow with brightness and contrast.  No success.  Someone suggested using Adobe Premiere’s 16-point garbage mask.  I combined my brightening and contrast with the 16 point garbage mask to isolate and lighten the shadow.  This worked decently and would have been an acceptable fix if this had not been in 3D.  However, the left image has such a strong shadow and the right image is so perfectly clear that the discrepancy causes retinal rivalry.  I was left with two solutions, minimize the difference between the two images or mono-ize the shot by removing the left and leaving the right.

In brainstorming solutions, someone suggested scaling the image up even more and cropping as close to the boy in the foreground as possible.  Though the shot is still slightly painful, it is much more comfortable to view than before.  However, this problem would have been avoided with a closer supervision of the left camera.  The consternation this clip caused raised an awareness in me of the necessity to monitor the left camera.  Because the right camera is easily monitored by the stereographer, the 1^st AC is key in confirming that the left camera image is also clear and good to go. 

 

Final Edited Framepack of Clip 1095

LESSONS LEARNED

1.  Recruit a 1^ST AC to monitor the left camera in lieu of field monitor viewing

2. Better to obsessively check the left camera in a split beam configuration than endure the pain of retinal rivalry and failed garbage masks