The mini beam splitter rig: portability for 3D documentary filmmakers

The mini beam splitter rig concept we came up with to film elements of our first 3D documentary has come to fruition.

We decided to try and build because the thought of moving and setting up our Film Factory 3D Indie BS Rig for one or two close ups is just too painful. Now we can use this smaller unit to shoot these components for the explosive demolition series Blowdown and save schlepping the full-sized rig around the Fonte Nova Stadium in Salvador, Brazil for when we’re shooting extensive B roll in one location.

The goal was to custom-design a rig that would house two Canon 7Ds and that was small enough and light enough to be operated by one person, handheld.

To achieve this, the mini beam splitter rig:

1) Has customized aluminum rails that aren’t as big and fat as the ones on the Film Factory Indie rig.

2) Is bolted and tweaked specifically for the dimensions of the Canon 7Ds.

3) Has a smaller box.

4) Is designed so the second camera is underslung – easier to handle because it’s not as top-heavy.

5) Allows us to get camera lenses closer to the mirror.

It was whipped up in a couple of days, and it’s not pretty – but it is portable and robust. We’ll see if it works.

Shooting a 3D documentary: building a mini beam splitter rig for close ups

Vision alert. So we’re thinking of designing our own mini beam splitter rig to shoot close ups for our first 3D documentary . Here’s why: as I’ve mentioned,we’re trying to sort out our B cam system using Film Factory’s 3D Indie BS Rig – this should hopefully work for the majority of our B cam shots.

But it isn’t the most portable system – something that will surely prove challenging on an industrial site, where the explosive demolition series Blowdown takes place.

For the odd close up of the crew loading explosives etc. in a condemned sports stadium in Salvador, Brazil, it’s painful to think about moving the whole rig and setting up just to get a shot or two.

And we’d like to avoid using a side-by-side rig  because it’s a mission (if not a mission impossible) to get the cameras close enough together to film these types of shots.

If there’s a way to build a mini beam splitter unit, one person could just move in and get this footage with way less trouble (ie. instead of two people to set up the full-sized rig, etc.).

As an added bonus, we could also use this system in a temporary pinch if the main B cam system happened to go down.

We bought an extra mirror anyway, in case the one that came with the Film Factory Indie rig system malfunctions mid-shoot … why not try and put it to use?

Our stereographer, Sean White, knows a machinist who may be able to help us build this mini rig we’ve envisioned.

We’d probably use Canon Vixias – smaller than the Sony EX1/EX3 combination we’re trying to make work with the Film Factory Indie rig – and rig it as an underslung system.

One camera would be positioned below (instead of above), and the spare mirror would be angled the opposite way as the one on the full-fledged beam splitter rig.

This rig would theoretically snap onto a tripod, and would achieve a small enough interaxial distance for us to get the close-ups we need without a mega hassle.

If any stereo, etc. issues arose, we’d correct them in post – theoretically a relatively small workload considering we don’t use tons of these types of shots in our shows.

At the moment, it’s just an idea – but seems fittingly par for this unchartered course.

3D beam splitter rigs for Sony EXs: filmmakers weigh in

It seems we’re not alone in the quest to find a beam splitter rig/camera system that will work as our B cam setup for shooting our first 3D documentary.

My previous blog outlining the issue has been posted on the Yahoo! Group thread P+S Technik 3D Stereo Rig + 2 Sony EX3, where there are entries from several people looking for information on how to make this – and similar systems – work for them.

Here’s our particular issue: we’ve been testing a Sony EX1 and a Sony EX3 mounted on a Film Factory 3D Indie BS Rig, but are having issues getting the cameras optimally positioned.

One alternative mentioned in the Yahoo! thread is a P+S Technik rig, but from what I gather it’s more expensive than the Film Factory Indie unit we’ve purchased.

Another up-and-coming alternative seems to be Alister Chapman’s “Hurricane” beam splitter rig, evidently designed specifically with Sony EX3s in mind.

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3D documentary filmmaking: why Sony EXs aren’t ideal for our beam splitter rig

A week of testing our B cam beam splitter rig system has revealed that the Sony EX1/EX3 duo we’re using with the Film Factory 3D BS Indie Rig aren’t ideal for shooting our first 3D documentary.

The issue isn’t technical – Alister Chapman reports using the same cameras successfully, and we were able to genlock the EX3 to the EX1 by connecting the EX1’s Y channel of the component output to the EX3’s genlock in connector, just as he has.

It’s logistical …the cameras are just too big and cumbersome for this particular beam splitter rig.

We’ve modified the rig so they fit better, but getting them aligned vertically is rough – the mics protrude and we’re still seeing the edge of the box and/or the bottom of the mirror when we use our Sony EX 5.8 mm lens (which has a 56-degree horizontal angle of view).

Wide shots are a must for Blowdown, the explosive demolition documentary we’ll be filming, so we need a system that will effectively capture this kind of footage – ie. we need to hit the sweet spot on the mirror, have the cameras vertically aligned and not see the rig when we use wide-angle lenses.

The alternative is enlarging the image in post to eliminate the part(s) of the shot that contain the rig, but that will degrade the quality, so I want to try and avoid this (especially since we’ll be blowing the footage up it to a certain degree already to facilitate convergence).

So, now we’re working with Canon Canada directly to get loaners of the XF305, which has just been released.

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3D documentary filmmaking: how to sync two Canon Vixias with one remote

As mentioned, I selected implosion cams for our first 3D documentary – six (three pairs) of Canon Vixia HF 10s and 12 (six pairs) of Canon Vixia HF M31s – a little while back.

Next, we needed to figure out how to turn each pair on simultaneously (the duos will be positioned to capture the implosion of a condemned sports stadium in Brazil for the explosive demolition series Blowdown).

And how to turn them on without knocking one (or both) out of alignment.

The cameras need to sit at a 74 mm interaxial distance, right next to each other, for us to capture the footage we need.

This means they’ll be positioned too close together for use to easily access the viewfinder on the right camera, where the camera controls are.

Since each camera comes with a remote, we tried to use them to adjust the settings on each one (holding two, trying to point each one at the infrared sensor on its respective camera), but it’s cumbersome and awkward.

It’s a problem: we need four elements to be in sync between before we start recording for these shots to work: the two cameras have to have the same zoom, the same white balance, the same exposure, and the same focus.

The risk of losing one or more implosion shots – our big bang footage that climaxes the show – because the crew’s running around like mad, trying to calibrate and turn these 18 cameras on properly while preserving their alignment, is a risk I’m not willing to take.

So our stereographer Sean White discovered a work-around – a home-made infrared transmission system that allows us to control both cameras at the same time.

With sourced components off the Internet, a box has been built that will receive any infrared signal and transmit it through a split cable to two infrared sensors.

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