Mastering 3D Mastering 3D

Mastering 3D
www.gtc.org.uk
With thanks to Merlin Entertainments for the anaglyph images from London Eye 4D
Experience (written and directed by Julian Napier and produced by Phil Streather)
This extreme shot from The London Eye 4D is 0.7% positive on the back of the
pod but 11.3% negative on the bubble being blown
can be too much 3D in the shot. There
is a very real danger of throwing
the baby of good 3D out with the
bathwater of gimmick.”
He advises viewing anaglyph images
of your 3D (in traditional red and
green), as this highlights the parallax
differences without the need for
glasses (see images above).
If you put all the 3D behind the
screen, it draws too much attention
to the viewing window (the screen
itself), “so you need some outie parts
of the picture.”
Depth of field
In Schklair’s view “It’s an urban myth
that you can’t have shallow depth of
field with 3D.”
“Some shots work really well
with shallow depth of field, others
don’t. If there is a really strong
subject, it can work well,” added
Andy Milns, Director, Inition, which
recently worked with Deeble & Stone
Productions on a beautiful 3D natural
history documentary that made good
use of depth of field. “Focus pulls can
look jarring, if it goes against the 3D,
but for action, where focus would shift
naturally, it can enhance it.”
Active or passive?
Passive rigs (ones that are set up
manually with the camera pair fixed
in relation to each other) are less
robust. You sometimes get movement
in the rigs that can cause alignment
problems. They typically use prime
lenses. Active rigs can correct for
the fact that no two zoom rings
match precisely and the camera pair
can be adjusted for convergence
and alignment but they require
specialist training.
The extra creative control allowed
by active rigs “is a really good idea
for documentaries, where you don’t
have the same sort of control in other
areas. They are bigger, but that is
changing,” said David Wooster of Can
Communicate.
Live electronic correction (basically
a sophisticated DVE) is also an option
– Sony’s new MPE-200 stereoscopic
image processor was recently used at
the World Cup. “You can fix a lot of
grievous errors in post. It’s expensive.
I don’t know why you’d want to do it.
But with live production you need to
use motorised systems,” said Schklair.
Streetdance 3D is claimed to have
been the first European production to
be shot digitally in 3D. It cost
£4.5 million and did exceptionally
well at the UK box office, earning
£2.4 million in its opening weekend.
It was shot using two fully motorised
rigs – one with RED One cameras and
a Steadicam unit with SI-2K cameras.
It took 40 days to shoot (two more
than budgeted – due to the weather
rather than 3D) and 18 weeks in
post (slightly more than a similar
2D production).
One of the decisions that has to be
made prior to production is whether
to shoot converged (which typically
requires using motorised rigs) and
merely sweeten the convergence in
post, or to shoot parallel (which would
allow using a passive rig) and do all
the convergence in post.
Although integrated camcorders,
such as Panasonic’s new AG-3DA1,
have a place in production, they
lack the control over the lens that is
necessary for some shots – close-ups
require lenses that are closer together
(typically in a beamsplitter or mirror
rig). There is still a need for a truly
lightweight, portable camcorder
without limitations, commented
Schklair.
“Using a beamsplitter rig can cause
exposure differences, which might
not be even across the frame, as
well as colour imbalance,” according
to Richard Wilding, senior editing
manager, Molinare. The facility
(which is currently working on three
3D productions) has worked with
Filmlight to adapt its Baselight system
to correct these differences, so that it
This anaglyph still from The London Eye 4D is 0.7% positive on the clouds and
4.2% negative on the seagull
can easily match colour and exposure
for both eyes.
Using a beamsplitter loses light; so
high speed filming is problematic as
it also loses light, making it difficult
unless it is extremely well lit.
2D to 3D conversion
Converting 2D footage into 3D was
a hot topic at 3D Masters. Some
successful 3D movies have been
produced this way, notably Clash of
the Titans and Alice in Wonderland,
done as an afterthought following the
commercial success of Avatar.
Prime Focus did a lot of visual
effects on Avatar, particularly on those
shots filmed with a single camera
(such as in tight locations or walking
through doors where a 3D rig wasn’t
practical).
“It gives you much more flexibility
and more control,” said Anshul Doshi,
group MD, Prime Focus. You can
decide scene by scene and shoot with
a film camera and save time on set.
Prime Focus also worked on Clash of
the Titans. “Because of the manpower
we had in India, we were able to do
it in eight weeks,” although it would
have been better to have16 or
20 weeks. However, it established
that the post process is possible.
The movie included some 2000
shots that had to be worked on,
with all the elements having to be
rotoscoped (cut out), so that the
client could then interactively play
“there aren’t enough people who can use
this gear – we need to train more crew”
Fact File
around with the depth. “It’s expensive
compared to low-cost automatic
systems from JVC and Panasonic.”
He didn’t mention a price, but 2D to
3D conversions can, apparently, cost
about $50,000 per minute.
Doshi believes that there are some
things best shot in 3D, such as sports
and concerts, but some shots might
be better shot in 2D and converted.
However, getting the best out of the
process requires planning, so you
won’t get the best result if you merely
add it to an existing 2D production.
David Fox is a journalist who has worked in TV and Radio as a writer,
producer and director, and writes regularly on TV technology for
TVB Europe. See his website at: www.UrbanFox.TV
Books and apps
For those interested in learning more about 3D production, Phil
Streather recommends reading: StereoGraphics Developers’ Handbook
(free pdf download – Google it); 3-D Filmmakers, by stereographer and
film historian Ray Zone (www.ray3dzone.com – £22.50 Amazon); and
3D Movie Making: Stereoscopic Digital Cinema from Script to Screen, by
Bernard Mendiburu (Focal Press – £31 or £17.50 on Amazon).
To help calculate parallax and separation, download: the RealD
Professional Stereo3D Calculator (£180); 3D Movie Calculator
(£18.50); IOD calc (£30); or 3D ST (£7.50), from Apple’s App Store
for iPhone, iPad or iPod Touch.
©MERLIN ENTERTAINMENTS
10 Autumn 2010 ZERB