About 3D
What are the basics of 3D?
See ‘
How it Works’
For more detailed overview,
Download Basic
Principles of Stereoscopic 3D
What does ‘z’ space mean?
In 2D, we are working only in terms of width and height – i.e. x and y axis. But
working in 3D means you can also work with depth –along the z axis, also known as ‘z’ space.
Good composition and blocking of talent, props, sets within ‘z’ space is crucial to making the most
of 3D.
Who is a stereographer?
The stereographer is responsible for creating comfortable 3D on all cameras and manages and
judges overall 3D quality. He / she works closely with the Director and DOP and together they
will work on the depth script.
What is a depth script?
This is a like a musical score; it outlines the amount of 3D (the depth budget) at particular
points in a script to underscore mood, emotion, to help the telling of the story. For
further reading on this subject, see
http://magazine.creativecow.net/issue/stereoscopic-3d
(Perception and the Art of 3D Storytelling, by Brian Gardner, Creative Cow Magazine- June 09
Stereoscopic 3D issue)
(NOTE BSkyB is not responsible for content on external sites.)
What is the ‘depth budget’?
The amount of 3D out-of-screen is known as ‘negative parallax’, on-screen as ‘zero parallax’
or the convergence point of the images; and into-screen as 'positive parallax'. The depth budget is
described as a percentage of parallax between near and far objects, behind or in front of the
screen and keeps the 3D within parameters that make for comfortable viewing. Sky’s
recommended depth budget of 3% (comprising positive parallax of +2% and negative parallax of -1%)
is a safe limit. The depth budget can be pushed beyond these boundaries to create a greater 3D
impact for short periods, but should be treated with care as prolonged period of intense 3d can be
extremely uncomfortable. If you have any questions, please contact us.
Note that producing 3D for cinema / Imax may require a different set of depth guidelines as
3% of a 20-foot screen will produce considerably more impact. Speak to us about all of your
delivery requirements.
Getting something commissioned by Sky 3D
Our production company has never done 3D before; would you still consider us for a 3D
project?
Yes - if you can show us that you are considering 3D in the right way.
Can you help us get funding for a co-production?
Speak to us; we can recommend partners you might speak to.
Can you help recommend 3D crew / experts?
Yes, speak to us – we have worked with a number of talented people we would be happy to
recommend.
Making 3D
What is a 3D rig?
A 3D rig is a structure holding two cameras together, one representing the Left Eye, the
other the Right Eye. The cameras must have matching geometry, exposure, colour balance, focus
and synchronized zoom.
What are the different types of camera rigs?
In a ‘side-by-side’ rig the cameras are mounted parallel. Due to the physical size of
the cameras and lenses, it is difficult to achieve small interaxial separation with a side-by-side
rig, so it is mostly suitable for medium and long shots.
The ‘mirror’ or ‘beam splitter’ rig places one camera horizontally, the other
vertically. A semi-transparent mirror reflects the scene into the vertical camera while
allowing the horizontal camera to see through the mirror. The mirror is fragile, dust prone,
reduces light by one f-stop and requires the image shot off the mirror to be flipped. The
right eye is generally the image shot off the mirror but this is not always the case. Colour
correction of one shot relative to the other may also be required. The interaxial distance on
a mirror rig can be as small as you want, even down to zero interaxial, so the mirror rig is very
suitable for close shooting.
What things should we bear in mind when budgeting 3D?
3D takes longer to do everything
3D costs more
Planning, preparation, testing, rehearsing, more testing will save you money in the end
Think about final deliverables early – will you be doing a cinema / Imax / blu-ray version in
addition to the TV broadcast version? This may have an impact on the number of cuts you need
and can affect how you need to shoot / edit.
Do you have any production tips?
Plan 3D first then 2D not the other way round
Spend time planning, preparing and testing kit
3D rigs can be big, heavy and time-consuming to set up so minimum travel / location changes
and controllable environments can save time and money
Due to the amount of time 3D rigs can take to set up. It is sometimes cost-effective to
have two simultaneous rigs– one to be used whilst the other is being set-up depending on the
conditions.
Airlines don’t like carrying big boxes and it can be very costly - so strip the 3D kit down
into smaller boxes. Just ensure you have an expert for re-assembly at the other end.
Can we hire your 3D OB truck and does it have crew attached?
Yes. Speak to Sarah Needham for details.
Can you help us with live 3D broadcasts?
Yes; at Sky 3D, we are very experienced at live 3D OBs (we broadcast the world’ s first live
3D opera – Mike Figgis’ Lucrezia Borgia as a quadcast (live in 3D on Sky 3D and to cinemas, live in
2D on Sky Arts 2, live 2D Director’s cut on Sky Arts 1); we shot the Got to Dance Final at
Kensington Olympia and have broadcast over 100 live 3D sports events.
Is the edit style different for 3D?
3D needs slower cuts in general. It take more time for your eyes to adjust from cut to
cut and this must be allowed for. In 3D, there is more information to take in and the viewer
needs time for their brain to process the information and to look around the space.
Can you help us with kit recommendations?
Yes, in our technical discussions, our experts can help recommend the most appropriate kit
for your production. We have worked with various companies we would be happy to put you in
touch with.
How important is set design / shot composition in 3D?
Very very important – use the space you have, the full ‘z’ axis, fully.
Do we need 3D monitoring capabilities on set?
Yes – always!
Can you help with technical questions?
Yes, we have some world-leading 3D technical experts – with any questions at all, please get
in touch.
3D Post Production
What are the stages in 3D post production?
Offline – it is always best to edit in 3D
Online
Corrections between Left and Right eyes, including:
- Geometry
- Alignment
- Camera matching
Grade
- Depth grade: cuts between shots with strong negative to strong positive parallax, or
vice-versa, can be very uncomfortable and quickly become visually tiring. The depth grade ensures
depth continuity (avoiding depth jump-cuts) to ensure comfortable 3D
- Colour grade: 3D requires more colour grading than 2D so this needs to be taken into
consideration when scheduling.
Delivery of Materials
What are your depth budget rules and how flexible are they?
3% (comprising positive parallax of +2% and negative parallax of -1%); graphic elements
can push these boundaries and there may well be other exceptions to this rule which would need to
be judged on an individual basis (see above). If you have any queries in relation to this,
please ask us.
What is the difference between true 3D and 2D-3D conversion?
By ‘true 3D’ or ‘native 3D’, we mean something has been shot in 3D using two cameras to
capture two unique images.
2D-3D conversion is when something has been shot in 2D and then ‘converted’ to 3D in
post. The types of conversion can range from an automated process (perceived addition of
depth; quicker but generally unsatisfying) to a detailed, meticulous process of layering 2D
elements in z space and painting in backgrounds as necessary that were not captured in the 2D
acquisition.
Given that 3D gives the viewer the ability to look around objects, to feel the
roundedness/depth of people, objects, landscapes and volume of space in a shot (and hence better
immersion in the reality of the story), it is extremely difficult to achieve this after the
event. Good conversion can be successful but it is usually extremely expensive and
time-consuming.
What is your allowance for 2D-3D conversion?
Our allowance is 75% true 3D : 25% 2D-3D conversion / 2D in one programme.
What is Sky’s preferred delivery format?
For final delivery: dual-stream HDCamSR tape (see tech spec and Delivery Requirements Summary
in Production Resources section for full delivery requirements) – if it is a movie longer than 62
minutes (without parts), we will accept separate SR tapes (one for each eye).
If delivering to our suites for in-house editing, dual-stream tapes are the preferred
delivery format but we do support certain files so long as agreed in advance.
What are the other formats 3D can be supplied on?
Single eyes on separate HDCam or HDCamSR tapes – only if longer than 62 minutes and not in
parts eg. A movie
Side-by-side on HDCam – by prior agreement only
Side-by-side blu-ray – for viewing purposes only
Can I use just one eye for the 2D version?
It will depend on the project. Often, a separate 2D edit is required for aesthetic reasons as
2D is a different experience to 3D.
Are there any useful reading materials on 3D?
(NOTE: BSkyB is not responsible for the content of any external sites)
There is lots of information out there. A couple of good books are the following (note
B Sky B is not responsible for the content of external material):
‘Foundations of the Stereoscopic Cinema’ by Lenny Lipton
Book: ‘3D Movie Making: Stereoscopic Digital Cinema from Script to Screen’ by Bernard
Mendiburu
Watching 3D TV
What is the difference between Passive and Active 3D systems?
There are two different 3D TV technologies in the market – Active and Passive.
Passive or Cinema 3D TVs use polarised screens to project both the left and right eye image
onto the screen at the same time, and then a special filter on the glass polarises the left and
right images differently, such that your 3D glasses then use a different left and right lens to
filter the correct image to each eye. Your brain then does the rest.
Active 3D TVs use powered LCD lenses which alternately ‘block’ one eye and then the other in
sync with the TV, which is alternating left and right images onto the screen at a very high rate
(usually a minimum of 50 frames per eye per second). This is fast enough that the brain sees no
gaps and again takes the two different views from the left and right eyes to merge them into an
image with depth.
What is the best way to watch 3D television?
Consult your tv manufacturer’s instructions but in general, being about 2 metres away from
the tv screen is best.
There are a number of ways in which you can optimise your 3D viewing experience:
If your 3D TV is an LED screen you may require time to warm up before the best possible 3D
picture is available. Please refer to your TV manufacturer for specific guidelines.
Ensure you follow your TV manufactures recommendations for viewing angles and viewing
environments. It is possible for example if your TV is wall mounted it may need to be tilted
forward to optimise the viewing experience.
Ensure your TV is using the latest firmware/software. Please refer to your manufacturers'
website for more information.
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