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IMAX 15 Perf Anamorphic

Why not?

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#1 Evan Prosofsky

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Posted 24 December 2013 - 04:38 PM

I've always wondered why there hasn't been a desire for 15 perf IMAX anamorphic footage. Surely, the tall IMAX frame is beautiful, but limiting in many ways, especially for those of us who don't like the aspect ratio jump when intercutting with other formats. I understand DOF would be insanely shallow and the lenses would be slow, but other than that, is there any reason this hasn't been considered??? I feel like IMAX anamorphic could be absolutely gorgeous and bring back a lot of interest to the format....


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#2 David Mullen ASC

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Posted 24 December 2013 - 07:32 PM

What's the point? You can't make the IMAX screen physically wider to accommodate a wider aspect ratio, so you just end up projecting a smaller (shorter) image, so why shoot 15-perf anamorphic if the image is going to be shown smaller? You might as well drop to 8-perf 65mm 2X anamorphic then if it's going to fill the same width screen as 15-perf 65mm spherical.
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#3 Evan Prosofsky

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Posted 25 December 2013 - 02:20 AM

I totally see what you're saying, but personally I would want the increased resolution for downscaling regardless of the size of the screen. I mean, the difference in screen size really isn't thaaaaat crazy. Recently seeing hunger games at the egyptian I didn't feel the jump from 35 anamorphic to IMAX image size wise was particularly massive, maybe thats just me... but the 35 anamorphic looked absolutely huge already, I just felt it was lacking in detail that the IMAX had.

 

Avoiding all the obvious difficulties like shallow focus, loud cameras, and expense, wouldn't somebody down the line have been interested in a widescreen IMAX image? Most IMAX lenses (if not all) to my knowledge are rehoused Carl Zeiss medium format, there's so much room for someone to design something new! Just my 2 cents :)


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#4 Gregory Irwin

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Posted 25 December 2013 - 10:03 AM

 
Avoiding all the obvious difficulties like shallow focus, loud cameras, and expense, wouldn't somebody down the line have been interested in a widescreen IMAX image? Most IMAX lenses (if not all) to my knowledge are rehoused Carl Zeiss medium format, there's so much room for someone to design something new! Just my 2 cents :)


It's not worth the extreme expense of 65mm IMAX when compared to 35mm cost.
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#5 David Mullen ASC

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Posted 25 December 2013 - 10:42 AM

I totally see what you're saying, but personally I would want the increased resolution for downscaling regardless of the size of the screen. I mean, the difference in screen size really isn't thaaaaat crazy. Recently seeing hunger games at the egyptian I didn't feel the jump from 35 anamorphic to IMAX image size wise was particularly massive, maybe thats just me... but the 35 anamorphic looked absolutely huge already, I just felt it was lacking in detail that the IMAX had.
 
Avoiding all the obvious difficulties like shallow focus, loud cameras, and expense, wouldn't somebody down the line have been interested in a widescreen IMAX image? Most IMAX lenses (if not all) to my knowledge are rehoused Carl Zeiss medium format, there's so much room for someone to design something new! Just my 2 cents :)


Wait, 15-perf 65mm spherical cropped to 2.40 isn't enough resolution to downscale to 35mm anamorphic or show in 4K digital projection? Again what's the point if there are no presentation systems in use in theaters that go show resolution beyond what you already get with 15-perf 65mm spherical? Why do you need even more resolution? I can understand a proposal for 8-perf 65mm anamorphic versus 15-perf spherical but there's no reason for 15-perf anamorphic if it just ends being shown in either 4K digital 2.40, 35mm scope prints, or regular 15-perf 65mm IMAX.
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#6 Evan Prosofsky

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Posted 27 December 2013 - 12:52 PM

This is the kindof thinking in film that frustrates me, you sound like producers ;)

 

"Its not worth the expense", and... "no one will notice, what we have is already good enough". I hear this everyday when I fight to shoot things on film :(, not 15 perf mind you, 4 perf 35.

 

A spherical crop from 15 perf to produce a 235 image is a massive crop. Thats why anamorphic exists.... same reason why they use it on 35mm. Yeah, cropped IMAX probably still looks incredible, but wouldnt anamorphic IMAX look that much better?!?! So don't understand your reasoning there.

 

Personally the film nerd in me wishes to see new formats created and experimented with despite how expensive they may be..... anyhow, I was curious to see if anyone knew of someone who had attempted to design this but sounds like not!


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#7 David Mullen ASC

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Posted 27 December 2013 - 01:16 PM

My reasoning is that why design some film format that tries to be better than 15-perf 65mm spherical if there is no venue or presentation technology that would see the improvement, considering the giant size of anamorphic lenses that would cover a 15-perf 65mm negative?  I don't mind doing more work or spending more money if there is going to be a visibly better quality image as a result, but in this case, until they make IMAX screens that are doubled in width, there is no reason to put an anamorphic lens on a 15-perf 65mm camera.

 

I don't see why you don't like the idea of 8-perf 65mm with anamorphic lenses, that would actually make some sense in terms of using a big negative and doubling the horizontal field of view for a 2.40 image compared to using a 15-perf 65mm negative and cropping it vertically if wasting negative bothers you.

 

CinemaScope was originally invented so that you could double the width of theater screens to show it while still using a 4x3 4-perf 35mm negative.  So doubling the width of an IMAX image but still showing it on the same width screen would result in no visible improvement in the quality of the 2.40 image compared to just cropping a spherical IMAX image.

 

Again, this is why I'm asking "what's the point?"  Why increase resolution if there is no way to see the increase in resolution?  And in truth, the horizontal resolution would be the same whether you shot 15-perf 65mm in spherical or anamorphic, only the vertical resolution would be increased.

 

Plus keep in mind the long focal lengths that IMAX has to use already due to the size of the negative and then double that for anamorphic photography, the depth of field would become even more insanely shallow.


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#8 Doug Palmer

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Posted 27 December 2013 - 01:53 PM

OK as it's Christmas, how about 8-perf 65mm with two letterbox images for 3D ? :rolleyes:

Has anything been done like this before ?

 




 

 

 

 

 

 

 

 

 

 

 

 


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#9 John Paul Palescandolo

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Posted 27 December 2013 - 03:27 PM

Wasn't Ben Hur shot on 65mm anamorphic? That takes the natural 2.20:1 aspect ratio of 65mm and makes it 2.76:1. That's a very wide frame and while by no means impossible to fill, it certainly takes more work than a 1.85:1 or 2.35:1 frame.

 

I think the frame size of an individual IMAX frame is around 52mm x 70mm, making it a tad bit smaller than a 6x7 frame in medium format photography, so using Carl Zeiss lenses to shoot IMAX makes sense.

 

As for doubling the lens focal length for anamorphic photography, is that something you have to do for 35mm anamorphic as well? Why is that necessary?

 

After seeing Catching Fire in 70mm IMAX and hearing about how shallow the depth of field is while using IMAX cameras, I don't remember the IMAX footage being dominated by really shallow focus.


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#10 David Mullen ASC

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Posted 27 December 2013 - 09:24 PM

"Ben Hur" was shot in 1.25X anamorphic on 5-perf 65mm.

 

I did a little math… IMAX negative is 70.41mm x 52.63mm, so it crop it to 2.40 gets you a negative that is 70.41mm x 29.34mm, which is a total square millimeter area of 2065.65.

 

So if you want to avoid wasting 15-perf 65mm negative to get a 2.40 frame, you'd have to shoot in anamorphic and get close to that 2065.65 sq.mm range to maintain a similar resolution (ignoring the fact that most spherical lenses are a bit sharper than anamorphic lenses).

 

5-perf 65mm is 52.48mm x 23.01mm and is already a 2.20 : 1 aspect ratio.

 

8-perf 35mm is 37.72mm x 24.92mm and is 1.50 : 1 aspect ratio.

 

My calculations show that 10-perf 65mm (vertical), which is a format that IWERKS made some cameras in, must be 52.48mm x 46.02mm.  That is a 1.14 : 1 aspect ratio, so if it gets cropped slightly to 1.20 : 1 and you use a 2X anamorphic lens on the camera to get a 2.40 : 1 image, you'd be using a 52.48mm 43.733mm negative area for a total area of 2295.13 sq.mm, which is slightly bigger than 15-perf 65mm spherical cropped to 2.40.  So you'd basically save 33.33% on stock by shooting 10-perf vertical anamorphic instead of 15-perf horizontal spherical and getting more or less the same negative area for a final 2.40 image.

 

8-perf 65mm would be 52.48mm x 36.816mm, which is a 1.4255 : 1 ratio, which is probably why it sometimes gets used for IMAX shooting (again, I think IWERKS made some cameras in this format). You'd have to trim the horizontal width to 44.18mm to get a 1.20 : 1 aspect ratio, so that with a 2X anamorphic lens, you'd get 2.40.  44.18mm x 36.816mm is 1626.53 sq.mm.


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#11 David Mullen ASC

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Posted 27 December 2013 - 09:35 PM

In theory, if a Super-35 negative that is 24mm wide tends to measure roughly 3.5K in resolution, even if scanned at 6K, then an IMAX negative using the same emulsion, which is 70.41mm wide, in theory would achieve around 10.2K in measurable resolution and should be scanned at well more than 12K to capture that without aliasing.  But that's in theory, in practice the lenses used for IMAX photography don't achieve the same MTF levels (because they don't have to) as the best 35mm cine lenses.  And I'm just talking measurable resolution on a negative, you can figure a contact print that is projected probably loses half that resolution, making IMAX print projection more like 5K, 6K at best.  So my guess is that a good digital substitute for IMAX would involve a camera with an 8K to 10K sensor with the final image projected in 6K.


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#12 David Mullen ASC

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Posted 27 December 2013 - 09:47 PM

2X anamorphic lenses basically double the horizontal view of the lens, so you'd use a 40mm anamorphic lens to match the horizontal view of a 20mm spherical lens if the negative format is the same width (4-perf 35mm anamorphic though uses the Academy Aperture width, which is closer to 22mm rather than the 24mm width of Super-35, so it's not exactly double in terms of matching views.)

 

So roughly, in terms of horizontal view, it's something like:

 

20mm spherical lens in 4-perf 35mm Academy

40mm 2X anamorphic lens in 4-perf 35mm

34mm spherical lens in 8-perf 35mm

47mm spherical lens in 5-perf 65mm

64mm spherical lens in 15-perf 65mm

...which means somewhere near a 120mm 2X anamorphic lens on 15-perf 65mm just to get the wide-angle view of a 20mm lens in 4-perf 35mm Academy Aperture.  So imagine the depth of field issues if your wide angle shots start near 100mm and your coverage is more in the 200mm to 300mm range.


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#13 Justin Hayward

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Posted 27 December 2013 - 09:55 PM

Personally the film nerd in me wishes...

 

I did a little math…  Blah blah blah blah, blah blah

 

 

Wait, who's the nerd?  Luv you David ;)


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#14 David Cunningham

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Posted 27 December 2013 - 10:08 PM

David. You rock! Although you are clearly a bit obsessed. LOL. I'll never watch IMAX the same way again. Now I kinda wanna shoot some. :)
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#15 Reuel Gomez

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Posted 28 December 2013 - 10:21 AM

Well damn...
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#16 Chris Burke

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Posted 29 December 2013 - 11:11 AM

such a venue to display all this resolution will probably come along sooner than later. After all, the trend has always been bigger is better. It is just that fewer people are filling said venue's seats. They will probably make one anyway. I know zilch about anamorphic lens construction, but my gut tells me it is easier to make a longer focal length anamorphic than a shorter one.


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#17 David Mullen ASC

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Posted 29 December 2013 - 11:37 AM

such a venue to display all this resolution will probably come along sooner than later. After all, the trend has always been bigger is better. It is just that fewer people are filling said venue's seats. They will probably make one anyway. I know zilch about anamorphic lens construction, but my gut tells me it is easier to make a longer focal length anamorphic than a shorter one.

 

The trend with IMAX has been to replace it with 4K digital cameras and projectors, which is not really a move upwards in resolution, but downwards.

 

Besides the depth of field issues with lenses that start at 100mm at the wide-angle end, front anamorphic designs are a bit like putting a wide-angle attachment in the front of the lens, which makes it much larger in front -- just compare a Primo anamorphic to a Primo spherical for example.  So I'm sure you could build some, but the lenses would be massive unless you opted for the simpler rear-anamorphic attachment approach.


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#18 Stephen Gelb

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Posted 03 January 2014 - 05:01 PM

thanks

 

does anyone know much about what lenses have and are being used for 65mm formats?


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#19 Poya Eivazmohammadi

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Posted 20 April 2014 - 07:00 PM

According to my calculations, if you were to use a 2x anamorphic lens on an IMAX camera, which has an aspect ratio of 1.43:1, you'd be getting a final ratio of 2.86:1. So while you'd be utilizing an enormous amount of negative on a format that has tons of negative as it is, making it look even better, you'd be sacrificing the height that IMAX can provide.
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#20 Will Barber

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Posted 21 April 2014 - 12:31 PM

If you shot the full IMAX frame with anamorphic and just projected it smaller so it'd fit on the screen widthwise, you'd get a tighter grain. But it does seem a bit excessive. Kind of the same idea as downsizing 4K to 1080. 


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