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IMAX vs. IMAX 70mm: The difference between these two cinema formats

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Re: IMAX vs. IMAX 70mm: The difference between these two cinema formats

#81

Post by qingcharles »

derbOac wrote: post #27
davidferguson wrote: post #14

If you want a very in depth technical look at the differences between IMAX 70mm, 70mm and 35mm for _The Odyssey_, I wrote an article about this last month. https://www.theppt.org/rewind/articles/where-can-you-watch-t... But here are my nit-picks from the article linked here. I'm only commenting on the 15/70mm IMAX parts, because I'm not knowledgable enough about the digital IMAX foramats. > The extra resolution, up t…

Not a complaint about your post but this stuff about film formats and aspect ratios has always had me scratching my head. For years I heard people arguing that wider aspect ratios were preferable because they afforded a wider view, and that narrower aspect ratios were too restrictive horizontally. This always seemed confusing to me because theoretically they should allow for more vertical space for the same width. No…

Don't want to particularly wade into an aspect ratio discussion, but the common thought around the standardization of 16:9 in home cinema/HDTV was due to the aspect ratio of human vision being somewhat of that ratio, due to use having two horizontally-spaced eyes.

Re: IMAX vs. IMAX 70mm: The difference between these two cinema formats

#82

Post by wuliwong »

jagged-chisel wrote: post #40
dbspin wrote: post #33

Earlier quoted context omitted.

Some directors like the appearance of film... Given that the spectacle is a large part of the reason we go to the cinema, the colour fidelity and (and in the case of IMAX) unique scale and aspect ratio are the point... Not sure why practicality or cost would override that? As a director who doesn't shoot on film - I still see the appeal, there's a particular quality to skin tones - especially in response to older arc…

I don’t understand how even the preference for shooting on film makes any sense if you’re digitizing, heavily processing, adding entirely digital elements … I get putting the final edit to film. If you’re not doing all that additional garbage, then capturing on film, going digital for basic editing, then back to film might make sense.

I cannot speak to film->digital->film but for audio recording if you did a similar thing like tape->digital->tape you would impart some real stuff to the recording versus just digital all the way through.

Re: IMAX vs. IMAX 70mm: The difference between these two cinema formats

#83

Post by tshaddox »

fsh wrote: post #9

IMHO, the only reasons for using 70 mm IMAX are nostalgia and marketing. Digital movie cameras have far better color reproduction, more dynamic range, zero frame jitter, and plenty of resolution without grain. They are also small and silent which allows far more interesting shots than what is possible with a 70 mm monster. Kubrick and Lean used 70 mm because it was the best technology available at the time. Today, th…

I think it's misguided to say things like "IMAX 70 mm has an equivalent of 18k resolution." But have you seen a 70 mm IMAX projection? In my experience, the 70 mm image looks noticeably sharper than an equivalent 4K digital IMAX projection.

1.43 IMAX 4K is also a great experience, but its resolution is a meaningful and noticeable limitation given its massive angular image size. It's a compromise compared to a more traditional 4K cinema screen (like a typical Dolby Cinema screen): with IMAX 4k you gain angular image size and lose "pixels per degree of visual angle." And both are noticeable!

I agree with you that the latter has all the advantages you listed, but there is still something truly special about the apparent resolution of IMAX 70 mm projection.

Re: IMAX vs. IMAX 70mm: The difference between these two cinema formats

#84

Post by tshaddox »

dbspin wrote: post #34
nottorp wrote: post #16

Earlier quoted context omitted.

I'd say one of the advantages of analog filming is it's more expensive to "color correct" digitally after. So maybe you get less monochrome films?

Every film is colour corrected and graded digitally (in addition to all the special effects and compositing work), and this is in fact one of the cheapest parts of the process. So no, it's not remotely a consideration.

Not every film. It was widely reported that Oppenheimer was color graded photochemically, and the 65mm film physically spliced (the editor of course worked in Avid with digital film scans). This means that 70 mm screenings were projecting a fully analog end-to-end pipeline. The exception, of course, is the visual effects shots, which went through a digital intermediary.

The same seems to be true of The Odyssey, although the reporting is less clear as of now, and I suspect there are many more visual effects shots than Oppenheimer.

Re: IMAX vs. IMAX 70mm: The difference between these two cinema formats

#85

Post by KaiserPro »

qingcharles wrote: post #79
davidferguson wrote: post #14

If you want a very in depth technical look at the differences between IMAX 70mm, 70mm and 35mm for _The Odyssey_, I wrote an article about this last month. https://www.theppt.org/rewind/articles/where-can-you-watch-t... But here are my nit-picks from the article linked here. I'm only commenting on the 15/70mm IMAX parts, because I'm not knowledgable enough about the digital IMAX foramats. > The extra resolution, up t…

18K seems high. I did some tests for Universal once and we pulled 10K from some 70mm IMAX ride prints. 8K was solid, 10K was very borderline.

I'm trying to remember what resolution we rendered two face for when it went into imax.

This was using 32bit renderman, and it was constantly OOM'ing because we were really pushing it.

I seem to recall that we rendered out at 7k, even though the optical resolution was meant to be 12k.

Re: IMAX vs. IMAX 70mm: The difference between these two cinema formats

#86

Post by dagmx »

davidferguson wrote: post #14

If you want a very in depth technical look at the differences between IMAX 70mm, 70mm and 35mm for _The Odyssey_, I wrote an article about this last month. https://www.theppt.org/rewind/articles/where-can-you-watch-t... But here are my nit-picks from the article linked here. I'm only commenting on the 15/70mm IMAX parts, because I'm not knowledgable enough about the digital IMAX foramats. > The extra resolution, up t…

Thank you very much for the corrections here. As someone else who has professionally worked in the film space, it always irks me when people talk about film in digital resolutions for the reason you mention.

I also agree with many of your other corrections but that is the one I wanted to ageee with the most as it’s my biggest pet peeve when I see people claim “film” is equivalent to a given resolution.

Anything analogue can be (almost) infinitely resolved but that doesn’t mean it’s going to be effectively good at all those resolutions. Almost nobody thinks of the quality of medium and lenses when making those claims.

Re: IMAX vs. IMAX 70mm: The difference between these two cinema formats

#87

Post by Marsymars »

tshaddox wrote: post #75
derbOac wrote: post #27

Earlier quoted context omitted.

Not a complaint about your post but this stuff about film formats and aspect ratios has always had me scratching my head. For years I heard people arguing that wider aspect ratios were preferable because they afforded a wider view, and that narrower aspect ratios were too restrictive horizontally. This always seemed confusing to me because theoretically they should allow for more vertical space for the same width. No…

Aspect ratio by itself tells you very little about the theatrical viewing experience. What really matters is the "angular image size," i.e. the horizontal and vertical angle that the image fills in your field of view. This is determined by the aspect ratio of the image, but also critically the size of the screen and the distance from the screen to the viewer. 1.43 IMAX screens are really really big and fill more of y…

> This is also why pleas for the 1.43 aspect ratio on home video are slightly misguided. It's not the shape of the 1.43 IMAX image that's so compelling. It's the angular image size! And you probably are not going to view an IMAX film at home with the intended image size.

Yes, exactly. If you really care about the theatrical experience, you'll be using a projector at home... and it's really up to your particular space whether you'd be able to fit in a bigger screen at a 1.43 or a 16:9 aspect ratio.

For some rough math, I rule-of-thumb 5 feet vertically as a reasonable max size for a home projector - it gives you a couple feet at the bottom for coffee tables, consoles etc. and doesn't reach too high, so you don't need to be looking too far upwards or to invest in stadium seating. 60 inches vertically gives you a 105 inch 1.43:1 screen, or a wider 122 inch 16:9 screen. Assuming you don't have other constraints (brightness, horizontal space, etc.) you may as well get the wider/bigger screen.

Re: IMAX vs. IMAX 70mm: The difference between these two cinema formats

#88

Post by Ccecil »

Some locals I know built a few of these cameras. I just ran into one of them the other day.

They started the local makerspace. There was an article last week in the local paper about it.

https://cdapress.com/news/2026/jul/25/couples-imax-camera-fi... {view it in a private window}

Re: IMAX vs. IMAX 70mm: The difference between these two cinema formats

#90

Post by Marsymars »

qingcharles wrote: post #81
derbOac wrote: post #27

Earlier quoted context omitted.

Not a complaint about your post but this stuff about film formats and aspect ratios has always had me scratching my head. For years I heard people arguing that wider aspect ratios were preferable because they afforded a wider view, and that narrower aspect ratios were too restrictive horizontally. This always seemed confusing to me because theoretically they should allow for more vertical space for the same width. No…

Don't want to particularly wade into an aspect ratio discussion, but the common thought around the standardization of 16:9 in home cinema/HDTV was due to the aspect ratio of human vision being somewhat of that ratio, due to use having two horizontally-spaced eyes.

wikipedia has the history of 16:9 - it originated as a compromise of the other popular aspect ratios at the time: https://en.wikipedia.org/wiki/16:9_aspect_ratio#History
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