Conference bookie::movies

I don't know the technical details, but from a viewer perspective, they are 
unbelievable!!!!! The Air and Space museum and Boston's museum of science both
have an OMNI theatre.    Although my five year found the experience too intense
I was astounded by it...

    RE: .1  by VIA::LILCBR::COHEN 
    
    >The Air and Space museum and Boston's museum of science both have an
    >OMNI theatre.    
    
    I believe Boston is an OmniMax and Washington is an Imax.  The former
    is more of a hemispherical screen, whereas Imax is "simply" concave.
    Personally I prefer the Imax because the seams tend to show more in the
    Omnimax.
    

    I was overwhelmed by the OmniMax at Caesar's Palace in Las Vegas.
    Last summer I saw a film there called Rain Forest. Whew! The next
    best thing to being there. 
    
    I really like the way the seats are set on a steep incline. A little
    unnerving if your'e afraid of heights but once the movie begins
    there are no 'big hair-dos' to get in your way. 
    
    Jodi-

    
    I really enjoy these type of theaters for the visual experience and
    the movie subjects. The quality of picture/sound is amazing. Here in 
    Colorado (Denver), there is an IMAX theater that's celebrating it's 
    10th year. They're showing a few of the old films as well as new ones. 
    The IMAX here is a flat screen, although it is about 4 or 5 stories 
    tall. I saw an OmniMax film once when I was in Boston and they're both 
    great. Here, they change films about every 3 months. Some of the ones 
    I remember are;
    
    Beavers (just saw this last weekend)
    To the Limit
    Chronos
    Grand Canyon
    The Great Barrier Reef
    The Blue Planet
    
    Does anyone have any technical info as far as what the film size
    actually is, etc.? Also where other theaters are located?
    
    Peter (at the CSC in Colorado Springs)

    
    I don't know the differences between Omnimax and Imax theatres,
    I suspect the differences in name may simply be different companies
    that supply the projection equipment.
    
    There is one here in Atlanta, at the Fernbank Science Center Field
    Museum. I have also been to one in Huntsville, Alabama, at the NASA
    space museum/Space Camp facility, and another in Chicago, at the Museum
    of Science and Industry.
    
    Curiously, all three theatres have a different "feel". The Atlanta
    facility has a huge (5 stories high) FLAT screen, while the other two
    have curved/panoramic type screens; almost like sitting in half of a
    planetarium, they even have similar high-backed reclining chairs.
    
    Although the flat screen is terrific enough, I really like the
    curved screens in Huntsville and Chicago, the effect is spectacular!
    In Huntsville I saw a film which contained several Shuttle launch
    sequences, including an awe-inspiring night launch. The effect of the
    curved screen made it feel you were there, close enough to feel the
    heat and smell the smoke coming at you from all sides. The day launch
    featured slow motion sequences from cameras mounted on the gantry
    itself.
    
    If you are in the vicinity of any of these Imax/Omnimax theatres, I
    recommend them; a bit pricey, but something very different!
    
    
    

    In The Liberty Science Center in Jersey City, there is an OmniMAx
    theatere and it is INCREDIBLE!!!! it is a dome that surronds you so
    that you feel as if you were actualy there. They are currently showing
    a movie called Flight of the Auquanaught, and it is breathtaking. Me,
    i'm for OmniMax.

    I saw "Ring of Fire" in Cincinnatis OmniMax and got motion sick, the
    U.S. Airforce museum in Daytion has an IMax, which is good but not as
    great as the "Omni"...

    RE: differences
    
    The OmniMax seats had you reclined looking up at the sphere on which
    the movie was shown.  I don't remember the seams, but the effect 
    (and affect) was awesome.
    
    The IMax seemed like a huge flat screen.  It may have had some curve to
    it, but it was slight as compared to the Omni.

    In Indonesia we have the big IMax theater (it was the biggest IMax
    theater as it was mentioned on the Guiness Book of Record, I think not
    anymore) The building is like a Snail. I heard now that the one in LA
    that show Rolling Stones concerts is the biggest now (?)
    
    I have seen The Blue Planet and Emperor of China also some Indonesian
    version (Beautiful Indonesia I & II, and Indonesia Children, you should 
    see if you go to Indonesia it's quite good)         

    RE: .5  by 29065::W_LATTA 
    
    >I don't know the differences between Omnimax and Imax theatres,
    >I suspect the differences in name may simply be different companies
    >that supply the projection equipment.
    
    I believe Imax and Omnimax were made by the same company.  Imax was
    their first attempt at this technology.  I don't know if they are
    responsible for the next generation of this technology which is now in
    use in one location in Japan which adds a 3-D element with each person
    in the audience wearing a set of electronic goggles which alternate
    frames from left eye to right.
    

    For the record... there's an IMAX theatre in Vancouver... I watched the
    afore-mentioned movie "Ring of Fire" (which was about the people and
    their efforts in sorting out the aftermath of the Gulf war. I think I
    recall a statement in the blurb for the theatre that the screen was 5
    storey's (sp?) high. The effect was certainly very real and I don't
    recall beaing able 'to see the join' on screen.
    
    I don't know what the following type of cinema is called, but in
    'Canada-land' at the Epcot centre there is a setup there whereby you
    stand in a large round room (and it's best to lean against the
    'podiums' provided). The cinema screen goes all round the room; is just 
    above head height (if you're a 6ft'er); and the screens themselves are
    probably about 10 ft high.
    
    The movie that was shown was about Canada and what you could expect to
    see and do there. The only way I can describe the effect is that in
    every scene, everything was in perspective. Eg. in one sequence the
    eight cameras were filming from the vantage point of a jet fighter
    aircraft which, in turn, was flying in formation with other aircraft.
    As I stood in the room and looked straight ahead, I could see open sky
    and the tail ends of two jets to my right and left; as I looked round
    the room there was (the side view of) a jet to my right; further
    around, and there were more jets (as in the nose of the jets were
    facing me); look directly behind me and I can see the tail fin of 'my'
    aircraft and the fuselage (sp?) etc; also directly behind me, is the
    helmeted head of 'my' co-pilot; carry on round the room and there are
    more jets on my other side as well.
    
    Of course when the plane banks to the left or right, you certainly feel
    as though you're in a plane... and the 'leaning on the podium' bit
    becomes all important.  I found it very easy to become disorientated.
    
    All of the film sequences were shot with eight cameras all
    strategically placed on some sort of cylindrical mount with the cameras
    pointing away from each other.
    
    The film was very well made I thought and your were left with a really
    perspective of waht Canada is all about.
    
    Another memorable sequence was when the eight cameras (don't ask me
    how) were attached to a skier skin down a mountain with other skiers
    who took great delight from cutting in front of 'you', etc; if you
    looked behind you could follow a skier as he/she caught up with you,
    passed you to your right/left and the accelerate away from the front of
    you.
    
    Hope all that managed to convey the effect; it's certainly worth a
    visit if yo visit the Epcot centre in Florida.
    
    Reargards,
    
    Stephen
     

Hi,

I'm the UK person Joyce refers to in 142.35 :-), and I'm glad she introduced me
to this conference as it looks full of interesting stuff!  Later on I want to
put a note in asking some questions, so I thought I'd get myself
in credit first by answering the questions asked in this topic! :-) 

IMAX was invented way-back-when (I think the concept began in the 60s, with the
first theatre in the early 70s) by three Canadian men.  They were basically
trying to solve the age-old cinema problem: how to get a bigger screen.

You can't just project standard film onto any size screen you want; if you go
too big, you start to see the graininess of the film.  Also the picture becomes
distorted, as the difference in distance of parts of the screen from the
projector becomes significant.  Finally, the power of bulb required to
illuminate a large screen starts to melt the film!

There have been various schemes over the years to get round the problem,
including such things as multiple synchronised projectors each projecting part
of the picture onto part of the screen.  These ideas didn't catch on, as they
were very hard (ie expensive!) to set up properly, and didn't give good results
(although they seem to have cracked it now with the cinema in the Epcot
Centre!).  The most successful system in the "olden days" was Cinemascope, which
squashed a big picture onto ordinary 35mm film, then used a special projector
lens to unsquash it again and give a wide picture.  However, this still suffered
from the graininess problem if you tried to go too big.  70mm film got round
that one, but still didn't satisfy the public's lust for even bigger pictures.

So this is where the IMAX story begins.  The Canadian gents surmised that to
get a bigger picture, you needed bigger film.  But for reasons I don't
remember (probably a lot to do with the cost and complexity of equipment
required) it wasn't feasible to go any bigger than 70mm film.  So they had a
brainwave: if they turned the film sideways, they could get bigger pictures on
it.  If that sounds daft, maybe a picture will help.

    |  |       / \         |  |   The picture on the left is a strip of 70mm
    |o |                   | o|   film (as you can see, it's from a home
    |  +-------------------+  |   movie of me waving at you all :-).  It's
    |o +-------------------+ o|   called 70mm film because the width of each
    |  |                   |  |   picture, or frame, is about 70mm.  The film
    |o |        o/         | o|   is pulled vertically through the projector,
    |  |       /|          |  |   and past the lens, by cogs/claws acting on
    |o |       / \         | o|   the sprocket holes at eachside.  As each
    |  |                   |  |   frame passes the projector lens, it gets
    |o +-------------------+ o|   projected onto the screen (surprise,
    |  +-------------------+  |   surprise :-).  As each frame is slightly
    |o |                   | o|   different from the previous one, it gives
    |  |       \o          |  |   the illusion of movement (eg me waving my
    |o |        |\         | o|   arms up and down).  It's obvious looking at
    |  |       / \         |  |   this that you can't make the picture any
    |o |                   | o|   bigger, or it would fall off the side of
    |  +-------------------+  |   the film.

But if you turn the film sideways, as in the picture below, you can make a
massive picture (no home movie of me this time, I can't afford an IMAX
camera :-).  This time the film is pulled sideways through the projector (and
the camera during filming!), and, hey presto, you have IMAX... but not quite.

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-------+ +--------------------------------------+ +---------------------------
       | |                                      | |
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The reason I say "not quite" is because conventinal projection techniques
didn't work with such a large frame size.  What happens in a projector is
that the frame stays still in front of the lens for as long as possible, then
is pulled suddenly away to make room for the next frame.  The projector bulb
is blacked out (by a shutter or rotating disc with slots in) while the film
moves to the next frame so that you don't see the film move, and your
"persistence of vision" helps stop you noticing that the projector is actually
flickering on and off (you can notice this by looking away from the screen so
that you can only see it out of the corner of your eye; the edges of the eye
don't have so much persistence).

The film must move from frame to frame quickly enough so that you can't see
the flicker, but as the frame size is now so big, there's too much film to
move in the time available (a fraction of a second).  The result is that the
film gets shredded.  The IMAX inventors dubbed it the "Autumn Leaves Effect",
as the projector sprays the shredded film around the projection room much like
leaves being blown by the wind.

Interestingly, they didn't have the same problem with cameras.  As you all
know, a camera shutter opens very briefly, in order to give a clear picture.
The film only needs to stay still while the shutter is open, so there is
plenty of time in between the brief shutter openings for the film to move
from frame to frame.

So, getting back to the projector problem, the IMAX chaps had to go back to
the drawing board and design a whole new type of projector.  What they came
up with was a large (more than a metre across, I think) carousel, which has
the film threaded around its edge.  You can see this carousel in the Boston
Science Museum Omnimax theatre, through the glass panels in the back of the
projection room.  It's the part that slides up the runners from the
table with the film spools to the projector lens in the auditorium.

The carousel is actually two (possibly more!) carousels one within the other
(I'm a little fuzzy on the details here, but the principle is right!).
One carousel moves in 'jerks', exposing one frame of the film to the lens,
then the next.  This gives the motion of the film required for projection.
The reason this doesn't shred the film is that there is quite a length of
film wrapped round the carousel, so the strain is spread over a larger area.
Also, the other carousel helps by feeding the film in one side continuously,
and out the other side continuously.

When you put the whole thing together, what happens is that the film is fed
smoothly and continuously into one side of the projector, and as it moves
round the carousel towards the lens, its smooth motion is gradually converted
to the jerky motion.  Because it happens gradually, there is no strain on the
film.  Once the film reaches the lens, it is in sync with the jerky carousel,
so gets projected properly, then as it moves around the carousel away from the
lens, it goes back to continuous movement, and leaves the projector smoothly.

No, I don't understand exactly how it works either... :-)

So that is the basis of IMAX: by using a much larger frame size, and a special
projector that can cope with it, you can project onto a much larger screen.
The first IMAX cinemas just had large
flat screens.  Then they went to curved screens, to try and fill the field
of vision.  The problem with this is that if you project an ordinary film onto
a curved screen, the perspective is all wrong and things look distorted at
the edges.  You need to make the film with a special lens on the camera so
that everything looks right when projected onto a curved screen.  Obviously
it's not feasible to make every film several times, with different lenses for
every cinema it's going to be shown at, so you just have to grin and ignore
the distortions.

OMNIMAX is just a logical progression from IMAX.  It uses exactly the same
film and projector technology, but has a hemispherical screen.  In order to
project properly onto this screen, the projector has to be right in the centre,
rather than in a projection room at the back.  This is why the projector
in Boston slides on runners: it would take up too much room in the auditorium
to have the whole projector in the middle, so they have the film spools (which
as you can appreciate, if you haven't seen them, are pretty big!) on reels
"downstairs", and the film threaded up to the projector carousels, lens, etc,
in the middle of the auditorium.

Just like the move from flat screens to curved ones, an ordinary film will
appear distorted when projected onto a hemispherical screen.  It's exactly
the reverse effect to putting a fish-eye lens on your camera and printing the
photos on flat paper: everything looks weird.  For Omnimax, you need a
fish-eye lens for everything to look normal!  The problem is, there aren't
many films made for Omnimax; as there aren't many Omnimax theatres, it isn't
cost-effective.  So most of the films shown at Omnimax theatres are
conventional IMAX ones.

Thus you get distortion at the edges, but this is no bad thing: when I was
feeling a bit nauseous from all the aerial antics we were watching, a quick
glance at the edge of the screen, which looked all bent out of shape, helped
to remind me that it's only a film :-)

Scott

Thanks for that excellent write-up.

I can't resist pointing out one semi-related fact: the VistaVision
format (very popular with special effects houses) is essentially the
same concept, but with 35mm film.  The FX folks use it to reduce the
grain problems with images that are produced from multiple generations of film.

    There is also an OmniMax in Portland, Oregon at the new Oregon Museum
    of Science and Industry (OMSI).  They said before the film that the
    projector alone cost 2 million.
    
    John

    
    
       Up here in Ottawa, Canada we have both Imax and Omnimax capabilities
    in one theatre.  They say this is the only museum in the world which
    offers both.  Is this true???
    
       P.S.  Anyone seen Titanica(imax)???
    
    Blair

I went to the IMAX at Fernbank Science Center near Atlanta over the weekend.
The movie was Antarctica and it was fantastic.  There are several helicopter
rides in the show and one of them nearly made me sick.  I actually had to 
close my eyes for a couple of seconds.

The screen is definitely concave, not flat as an earlier replier thought.

We took my son for his birthday and now we're all hooked.  We'll go back
every time they change the show.

Bob

    Are you sure it wasn't an OmniMax theater you went to?  Although I
    believe the IMAX technology was designed for a flat screen, I bet
    the could project it on something else.

    It think the main difference is the photographic technology.

    Like I said, the IMAX at Wright-Patt AFB is a huge flat screen, and the
    OminMax in Cincinnati is a spherical theater.

>    Are you sure it wasn't an OmniMax theater you went to?  Although I
>    believe the IMAX technology was designed for a flat screen, I bet
>    the could project it on something else.

Well, I wouldn't know the difference but all the signs and literature call it 
Imax.

Bob

    See also note 1104.
    
    I went to the Vancouver theatre last weekend and saw "Wings of Courage"
    in IMAX-3D.
    
    1. The screen was flat, or very nearly so. Advertised as 5 stories
       high; I calculated it was 8 door-heights which would be about right.
    
    2. The "goggles" we got were not anything fancy. They were large-framed
       and quality plastic. Each lens contained a fairly strong but flexible
       dark green-gray filter. My guess would be polarizing filters.
       Think of maybe 5 thicknesses of Saran Wrap painted the background
       color behind the face on the front of U.S. currency. That was what
       you looked thru. (OK, OK, not quite as dark as that...)
    
    3. Goggles were just big enough to cover my glasses, so I don't think
       anyone had any trouble seeing the picture. I took off my goggles 
       while the credits were rolling and saw two offset sets of letters.
       Overlapping maybe 80%.
    
    4. The movie was about 40 minutes long and cost C$8.50.
    
    I would describe the plot as "adequate", the acting as "decent", and
    the technology as "astounding". Basically if you're ever in the area
    you should make the time -- hardly more than an hour -- to catch any
    IMAX-3D movie (note: the "3D" is important). It is just incredible the
    way things come out at you from the screen. No vertigo for me, just
    lots of fun!
    
      John