3D Workshop: Faraway Flatness, Faraway Softness

 Get out your anaglyph glasses!

In my first post about the Gokinema 3D Workshop I attended in Sweden, I noted a few basics concepts: edge violation, screen distance and IA (inter-axial), to complement my article in the November issue of American Cinematographer

I now share two of the simple tests we shot to evaluate the look of distant 3D backgrounds, which I call faraway for short. When watching 3D movies I have often been struck by how objects at distances of more than a hundred meters have a different quality, often lacking the depth we perceive with our eyes. Geoff Boyle‘s 3D workshop in Gothenburg was a great opportunity to begin exploring the faraway image.

Once again, if you don’t already own some, I heartily encourage you to obtain a pair of cyan red cardboard glasses. And once again, I must stress that I am just a student of 3D, not an expert.

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thomas-harbers-greenpost--thefilmbookThomas Harbers assisted Geoff Boyle with the course, providing post-production for the 3D footage we shot.

Thomas is a man of many talents: in addition to 3D production and post services, he also does CAD and invents gear; his latest offering is DasRekorder, a file-based recorder for 3D video streams. Thomas kindly prepared the anaglyph movies from the workshop for this post.

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faraway flatness

The YouTube icon below displays the separate left and right views, once you click the play arrow, the video will combine them in an anaglyph.
I recommend looking at this full screen.

In case of playback problems, try viewing here

We shot this scene converged with 2 small SI-2K cameras mounted on a Stereotek rig, using 16mm Zeiss Ultra Primes. The point of conversion was about 10 meters, the nearest distance to the incoming boat. There is a HIT of 0%, in other words Thomas left the images as is. (Note that the bottom-screen info is wrong).

This footage illustrates how faraway objects in stereo 3D often look flattened. The bridge in the distance almost looks like a painted backing, except for the moving cars.

thefilmbook  3D workshop - faraway flatness - pier and bridge

(click for larger image in separate window)

The flattening effect is most noticeable to me when the incoming boat is seen in front of the bigger vessels behind it. The foreground ferry’s volume makes the background ships seem that much flatter.

thefilmbook 3D workshop - faraway flatness - nearby and faraway boats

(click for larger image in separate window)

Thomas comments that “this is an impossible shot, you can’t make both the distant objects and the close objects look good”. The lesson here is that it’s the combination of deep nearby and flat faraway objects that doesn’t work.

Stereographers will point out that our perception of depth disappears with distance, yet the flattened faraway here still seems unnatural to my eye. You can give distant objects a little more depth by increasing the IA (interaxial distance), with the risk of miniaturization — seeing the world through a giant’s eyes. Here we used an IA of almost a meter, and we didn’t notice any miniaturization. Next time I’d like to try IAs of 5 or 10 meters, to see how much depth we could give the faraway boats or bridge. As Thomas points out however, a huge IA could make the nearby objects look unnatural.

Another lesson in this test is that receding lines and volumes, like the pier at the beginning, help the perception of 3D, by giving us a continuous transition between nearby and faraway objects.

Note also the edge violation at the beginning, with the pier popping out of the screen.

thefilmbook-3D-Workshop-Chiel-van-Dongen-with-SI-2Ks-on-Stereotec-rig-

AC Chiel van Dongen with the SI 2Ks on the Stereotec rig, before we increased the IA.
(click for larger image in separate window)

And if you’re wondering, yes, the Gothenburg harbor was COLD!

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faraway softness

In case of playback problems, try viewing here

Most stereographers will recommend shooting with a big depth of field to get good stereo 3D. So naturally I wanted to see what a very shallow depth of field looked like in 3D. We shot this with 2 Alexas on a Quasar rig, closing the shutter to allow us to open the iris all the way.

I really like the way this test looks. In my opinion this effect would work well for some stories or scenes. In a sense, the soft focus background helps make the flattening of the distant buildings less noticeable… and more pleasing to my eye. Low depth of field could be one way of blending deep nearby objects and flat faraway backgrounds. Post specialist Cedric Lejeune cautions that very soft focus could prove hard for both eyes to fuse when seen on a large screen.

thefilmbook 3D workshop - faraway softness

(click for larger image in separate window)

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big rig

thefilmbook Yke Erkens from Camalot with Element Technica Quasar rig with 2 Alexas and Transvideo

Before we went outside Yke Erkens from Camalot in Amsterdam showed us the Element Technica Quasar rig loaded with 2 Alexas and a Transvideo stereo monitor

thefilmbook Moving Quasar rig across treacherous icy paths

Yke and Chiel wrap their Quasar rig across the treacherous icy path
(click for larger images in separate window)

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links

greenpost Thomas Harbers’ bilingual site — an eu domain
GoKinema 2012 will reprise workshops and master classes for filmmakers
My first post about the 3D workshop: egdes, screen, IA…

All photos by Benjamin B

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Your comments & corrections are most welcome. I’d love to hear of opinions or experiences shooting stereo 3D with distant objects, or shallow depth of field…

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