P3D Large screen 3D alignment (was: IMAX in London)

[Andrew Woods <andrew@xxxxxxxxxxxxxxxxxxxxx>]

bob.aldridge@xxxxxx (Bob Aldridge) wrote:
>Yesterday I was lucky enough to get into a (well, actually two...)
>preview of the new IMAX cinema in London at the Trocadero.
>
>It will open officially on Tuesday showing several flat (2D) films plus
>Across the Sea of Time in 3D.
...
>I do, however, wish the projectionist would push the image a bit further
>back - they seem to have "mounted to infinity" at the screen!!! i.e. the
>infinity points are co-incident on the screen and everything extends
>into the auditorium. 

I visited the new IMAX 3D theatre in Darling Harbour, Sydney the week
before last.  They are currently screening two 3D films: Across the
Sea of Time and Nutcracker.

I saw both films and also noticed problems with the infinity setting 
of the projected 3D image.  In this case the infinity point was actually 
in front of the screen - and by quite a substantial amount.  Both films
seemed to have the same setting.

Although 3D has more impact when it comes out of the screen, 3D is easier
on the eyes if you pay attention to the accommodation/vergence conflict
and project images +/- from the screen.  (In this case all the images were
projected in front of the screen).

On a slight tangent from this topic - I keep in trying to think of a
way of measuring visual angle easily while I'm watching 3D movies.
I'd like to be able to measure the amount of vertical parallax on the
screen and where the infinity point is set to.  Any ideas?  Perhaps
a toilet roll tube with a piece of clear plastic stuck to one end onto
which is printed a scale...

I saw both movies.  I though Across the Sea of Time was great.  On the
other hand I thought Nutcracker was wierd.  My wife liked it although
she did say that she was familiar with the Nutcracker story.  I certainly
don't think it benefits any from being in 3D.

I wonder whether IMAX has recommendations of the correct (horizontal) 
alignment of the projected image.  I presume they would but two
cases (London and Sydney) indicate that maybe they don't or possibly
alignment procedures are not being followed.

Andrew Woods.              http://info.curtin.edu.au/~iwoodsa


27 days to go to the Stereoscopic Displays and Applications Conference
       http://info.curtin.edu.au/~iwoodsa/stereoscopic


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