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IMAX look vs 35mm look


Alan Kovarik
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Can somebody elaborate why a movie shot on IMAX has a different look than a movie shot on a regular 35mm camera? I am not talking about the aspect ratio and screen size (IMAX movies looks more monumetal even on ordinary television).

Edited by Alan Kovarik
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If an IMAX movie looks different from a regular movie, it would be because the IMAX image has way better steadiness due to register pins that locate each frame very precisely. Only studio background projectors have precision movements, the common 35 clappers pull on the film via an intermittently revolving sprocket drum. The IMAX projector has shutter edges moving horizontally across the screen (too fast to be visible), 35 equipment has some sort of vertical blinding. IMAX has better technical sharpness based on the film being vacuum sucked to an aperture glass, frame by frame. Besides these basic facts maybe more wide-angle lenses are in use for IMAX, depth of field shorter, and the cutting pace seems to be slower. The cameras are rather bulky and heavy, so hardly any hand-held shots are seen with IMAX. Last, I don’t know of a black-and-white IMAX movie, they’re all in colours. 35 was only black for decades and still can be so.

Also interesting to ask what discerns 35 from wide film

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So why movies shot on IMAX looks so epic even on TV? I think it has to do with the size of the frame (because on IMAX cameras you need to use longer lenses which has specific effect). But can somebody describe it what is happening here?

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Lens perspective (relative sizes of objects near to far) is determined by camera position, not focal length, which just controls degree of magnification. 

What you see in IMAX movies on a TV screen, besides just clean, sharp photography, can be the shallow focus of wide-angle shots due to the lower depth of field (because longer focal lengths have to be used to achieve wide-angle views on bigger formats).  There is also a tendency in IMAX photography to shoot almost fish-eye wide-angle shots because they are meant to be seen on very large screens where you sit very close.

See:

http://www.yedlin.net/NerdyFilmTechStuff/MatchLensBlur.html

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It's also worth pointing out that more surface area equals more colour, and more practical DR (though not per unit area).

Jonathan Schwartzman (DP on Jurassic World) says that the larger the format, the lower the contrast. I don't know what he meant exactly, but more colour, and better shadow details, due to more surface area, would probably qualify as 'lower contrast' I suppose.

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But wide shots on IMAX looks more natural and lifelike, because they are less distorted, right?

I am not sure it is only about the depth of field and wide shots. Even large format portrait or product photography has a specific look.

Edited by Alan Kovarik
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Apart from tracking and craning shots,  there's very little camera movement. At least in the Imax films I've seen. The action is allowed to take place in a more leisurely fashion, similar to the old Cinerama, with more screentime needed to take it all in. And I've noticed often the main subject with say a person in mid closeup, happens in the lower central part of the frame, where your eyes are naturally placed.  Haven't seen TV Imax, but would think it would'nt work too well.

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13 hours ago, Simon Wyss said:

Nah, you don’t sit very close to the screen. It fills your field of view more, that’s the point.

 

 

Same difference… my point is that compared to a regular cinema screen, you sit relatively closer in terms of screen heights because the image resolution allows it.

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8 hours ago, Alan Kovarik said:

But wide shots on IMAX looks more natural and lifelike, because they are less distorted, right?

Are they? I don’t see any difference in lens distortion, in fact, IMAX movies often have semi-fish-eye shots and corner fall-off issues.

271CEF07-EE23-4198-B13A-68680FC6F9C2.jpeg

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3 hours ago, David Mullen ASC said:

You’re falling into believing that myth that larger formats somehow give you wider shots that are less distorted because they use longer focal lengths.

Yes, in lens design it’s not actually focal length that determines distortion, but angle of view. A 20mm lens made for S16 format for example is a normal focal length, with about a 33 degree angle of view and usually little to no distortion. But designed for a full frame camera, a 20mm lens needs to cover 84 degrees and is an extreme wide angle. The lens designs would be completely different, with much more distortion likely in the full frame lens. 

Modern lenses are becoming much better at distortion control, in terms of keeping things rectilinear, but the simple physics of squeezing a wide view into a single image necessarily stretches the shapes of objects at the edges. It has nothing to do with focal length per se. Anamorphics and zooms are more prone to distortion, but that tends to relate to design, angle of view and zoom range rather than simply focal length.

The other cause of distortion is perspective, which is a factor of distance to subject. The size of the format again plays no role in that.

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A 70mm/15-perf negative records an incredible amount of information that gives these films a “look” closer to medium format portrait photography. When viewed on a big screen you see color, detail and scale that is differentiates it from 35mm and digital projection. Of course seeing The Dark Knight on a Home Screen looks great, which is attributed to the quality of shooting on the largest format for motion picture. You can see it for yourself in Nolan’s movies: when Dunkirk was in theaters, I saw it on IMAX 70mm/15perf dome, standard 70mm, and digital IMAX. The former made a huge screen into a window into a different world. Standard 70mm presented a very high quality experience for viewing a blockbuster. Digital IMAX in comparison was similar to a home viewing on a Tv. To best understand IMAX is to personally view a 70mm print; an easier way is to compare prints from 35mm and medium format still-frame photography. Obtaining an optical print of these show a level of clarity and color that is still difficult for screens to depict, and shooting on a larger negative helps to give a unique look and quality to the image. 

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On 9/24/2021 at 5:57 PM, Jonathan Hornby said:

A 70mm/15-perf negative records an incredible amount of information that gives these films a “look” closer to medium format portrait photography. When viewed on a big screen you see color, detail and scale that is differentiates it from 35mm and digital projection. Of course seeing The Dark Knight on a Home Screen looks great, which is attributed to the quality of shooting on the largest format for motion picture. You can see it for yourself in Nolan’s movies: when Dunkirk was in theaters, I saw it on IMAX 70mm/15perf dome, standard 70mm, and digital IMAX. The former made a huge screen into a window into a different world. Standard 70mm presented a very high quality experience for viewing a blockbuster. Digital IMAX in comparison was similar to a home viewing on a Tv. To best understand IMAX is to personally view a 70mm print; an easier way is to compare prints from 35mm and medium format still-frame photography. Obtaining an optical print of these show a level of clarity and color that is still difficult for screens to depict, and shooting on a larger negative helps to give a unique look and quality to the image. 

Another thing that separates 15/70 Imax from all other formats (including digital Imax).... the extreme height. In fact, depending on your seat it's sometimes not possible to see part of the base of the frame. Perfect for accentuating high places or creating vertigo 😆  And it's sometimes disappointing  I find,  when Nolan changes abruptly to normal 70mm height.

We shouldn't forget that 15/70 Imax has been a highly successful format worldwide, since its creation way back in 1967. Cameras and projection ingeniously designed.

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On 9/23/2021 at 10:56 AM, Alan Kovarik said:

But wide shots on IMAX looks more natural and lifelike, because they are less distorted, right?

I am not sure it is only about the depth of field and wide shots. Even large format portrait or product photography has a specific look.

The idea that larger formats gives less distortion (on equivalent focal lengths) is 100% a myth, but an often repeated one.

The video below shows the differences and how to some extent you can account for the differences in DOF / back blur, which is simply a product of longer focal lengths used (on larger formats) to achieve a specific angle of view.

 

 

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On 9/22/2021 at 9:50 AM, Alan Kovarik said:

Can somebody elaborate why a movie shot on IMAX has a different look than a movie shot on a regular 35mm camera? I am not talking about the aspect ratio and screen size (IMAX movies looks more monumetal even on ordinary television).

Part of the look, is the heavy camera and depth of field, which "can" look more shallow because of longer length lenses used. The heavy camera means the way you shoot with the camera is more restrictive. Nolan was one of the first filmmakers to use it hand held, but even then, on films like Dunkirk and Tenet, it's completely indistinguishable from the 5 perf material outside of the image crop change. 

On 9/22/2021 at 1:43 PM, Alan Kovarik said:

So why movies shot on IMAX looks so epic even on TV? I think it has to do with the size of the frame (because on IMAX cameras you need to use longer lenses which has specific effect).

Na it really doesn't, again just look at Dunkirk and Tenet. 

On 9/23/2021 at 2:56 AM, Alan Kovarik said:

But wide shots on IMAX looks more natural and lifelike, because they are less distorted, right?

 It can be less distorted because you use longer lenses to get wide shots. But you can do the same thing with 4 perf 35mm or Vista Vision. 

What makes 15 perf IMAX such a special format is it's high resolution and unbelievable registration/bright projection system. It's more of a projection format than a camera format honestly, because the camera tech isn't too special, but the projection format is very unique and it's sadly dead. 

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2 hours ago, Tyler Purcell said:

What makes 15 perf IMAX such a special format is it's high resolution and unbelievable registration/bright projection system. It's more of a projection format than a camera format honestly, because the camera tech isn't too special, but the projection format is very unique and it's sadly dead. 

Interesting. I have not heard this before. Where can I read about this in greater detail?

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52 minutes ago, Karim D. Ghantous said:

Interesting. I have not heard this before. Where can I read about this in greater detail?

I have seen this some data before... but even more convincing as seeing it projected in several of Nolan's 70mm IMAX releases; the images are bright and rock steady. If you know how a basic projection works, there's little difference from a 35mm theater system to that of a modest 8mm home projector. IMAX changed that with a revolutionary system for their film. This recent video showing the last viewing for a particular IMAX theater shows off the ingenuous design:

 

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It's a myth that large formats allow you to shoot wider-angle shots with less distortion because of the longer focal lengths used.

When people use the word wide-angle "distortion" they usually mean either perspective distortion (exaggerated size of foreground elements compared to background) or optical artifacts like barrel distortion, fall-off, etc.  Neither have anything to do with the size of the format.

Relative size of foreground objects compared to background objects is not a focal length issue, it isn't even a lens or camera issue at all -- it happens with your own eyes. It is due to your position as a viewer (or a camera) relative to the objects in front of you.  If you are standing in a line of people, the back of someone's head might be very close to you and be very large in your field of vision compared to some distant object, but back away from that foreground head and it becomes smaller relative to the background objects. The focal length of the lens only magnifies that view, it doesn't change relative sizes. 

I was driving along the highway and saw the Full Moon rising and saw a Union 76 gas station approaching and was hoping to find a camera position where the Moon and the orange ball sign above the station were the same size, and then use a telephoto lens to make them both fairly large in the frame.  But the alignment from the highway was off and as I got closer to the gas station, the orange ball sign became larger than the Moon in the background.   The two relative sizes were determined by my position in space.  It's the thing when photographing a face in close-up -- if the camera gets physically too close, the nose is much larger in size relative to the ears.  That is true whether the camera had a 10mm lens on or a 1000mm lens on, the only difference would be that the 1000mm lens probably would only hold a small part of the face in frame.  But the distortion of areas of the face relative to each other,  the large nose and small ears, would be the same.

The other type of wide-angle distortion -- barrel distortion or corner fall-off, are not unique to lenses made for smaller formats. In fact, some older lenses made for large formats show quite a bit of these artifacts compared to some modern lenses made for smaller formats.

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3 hours ago, Tyler Purcell said:

Part of the look, is the heavy camera and depth of field, which "can" look more shallow because of longer length lenses used. The heavy camera means the way you shoot with the camera is more restrictive. Nolan was one of the first filmmakers to use it hand held, but even then, on films like Dunkirk and Tenet, it's completely indistinguishable from the 5 perf material outside of the image crop change. 

Na it really doesn't, again just look at Dunkirk and Tenet. 

 It can be less distorted because you use longer lenses to get wide shots. But you can do the same thing with 4 perf 35mm or Vista Vision. 

What makes 15 perf IMAX such a special format is it's high resolution and unbelievable registration/bright projection system. It's more of a projection format than a camera format honestly, because the camera tech isn't too special, but the projection format is very unique and it's sadly dead. 

I wonder if a contributing factor to this perception that 70mm and IMAX has less distortion might be due to the lack of lens choices. It is my understanding, for instance, that only Panavision made anamorphic lenses for standard 70mm, and they only made a single set. Seeing Hateful Eight projected in 70mm, shot on Ben Hur anamorphic lenses, still looked really clean... so, with only spherical prime lenses and a single set of anamorphics from Panavision available, Its easy to see how such films have less visual distortion than a great deal of other productions that had more tools (and dear I say shortcuts?) available. It is also a nice novelty to view old family movies from the 1950s onward, shot on 70mm and viewing on a recently mastered Blu-ray, and think that it could have been shot yesterday. 70mm is indeed the gold standard.

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It's very sad indeed if as Tyler says, 15/70 projection is now dead.  A 54 year lifespan isn't bad, though I'm sure many devotees like myself would still support the cost of providing those mammoth rolls of film.

I think Simon mentioned: unlike 35mm there haven't been any monochrome Imax's during this time.  I wonder why. It would be great to see something like Ansel Adams-type footage of Yosemite and so on,  not to mention the many creative possibilities of chemical black and white film projected on to that vast screen.  Maybe indies should take over...

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9 hours ago, Doug Palmer said:

 I think Simon mentioned: unlike 35mm there haven't been any monochrome Imax's during this time.  I wonder why. It would be great to see something like Ansel Adams-type footage of Yosemite and so on,  not to mention the many creative possibilities of chemical black and white film projected on to that vast screen.  Maybe indies should take over...

Reading that made me think 'if Conrad Hall was shooting Imax ... ?' and of course, that IN COLD BLOOD pane of glass with rain falling across Robert Blake's face came to mind, but up  on an Imax screen, and perhaps done with even more prep and subtlety.

Geez, B&W and real Imax could have been an incredible combination. Now I'm thinking David Lynch in the early 80s might have been ideal to pair with it.

There's an alternate reality where the manned space program didn't stall/die out with Apollo and Timothy Dalton started doing Bond movies with FOR YOUR EYES ONLY ... maybe it's the same one where Doug  Trumbull's Showscan revolutionized filmmaking and the only way Imax could compete for large-format was by giving Lynch carte blanche, partnering with DeLaurentis to do DUNE in B&W (perhaps with desert scenes tinted or hand-colored a la old B&W films.)

Oh, if wishes were sandworms ... you'd all be eating my Arrakeen dust.

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10 hours ago, Doug Palmer said:

It's very sad indeed if as Tyler says, 15/70 projection is now dead.  A 54 year lifespan isn't bad, though I'm sure many devotees like myself would still support the cost of providing those mammoth rolls of film.

It's a wholesale issue; increased print costs due to less being made, increase equipment maintenance costs and labor. 

The liquid cooled lamp is $20k and lasts around a month of continued use. 

The projector burns through PTR rollers and cleaning supplies. Vacuum systems need to be maintained as well. So service/labor costs are high to keep it running. 

IMAX projectors (in most cases) aren't owned by the theater, they are leased. Today IMAX is allowing theaters to keep their 15/70 projectors if they want, without increased leases which is nice. But the other costs of course exist. 

So if you do all the math, there is very little room for profits with 15/70 projection, which is partially the reason why most real IMAX theaters were originally science museum based, far more profits as you can run more screenings in a given day. But with the industry shifting to theatrical, with less profits, it was a no-brainer to switch to digital. Now they only have to pay for the lease, no lamp's (laser light source), no specially trained staff, no crazy print costs. 

So yea, 15/70 projection is pretty much dead. There are a few theaters with their film projectors left, but very few. The dome theaters are nearly entirely changed over, which is the real sad part because sitting that close to the screen, really needs high res and replacing it with a 4k system is just crazy. 

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13 hours ago, David Mullen ASC said:

When people use the word wide-angle "distortion" they usually mean either perspective distortion (exaggerated size of foreground elements compared to background) or optical artifacts like barrel distortion, fall-off, etc.  Neither have anything to do with the size of the format.

This is very cleverly worded because you're right, they have nothing to do with the format. 

But you would agree, that longer lenses in general, do have less barrel distortion. 

So to get a "wider" shot with a longer lens, one would need to increase the imager size right? 

 

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3 hours ago, Tyler Purcell said:

But you would agree, that longer lenses in general, do have less barrel distortion. 

For lenses designed for the same format, maybe. Less and less so with modern lenses though, which tend to be well corrected for distortion.

But as I explained earlier, distortion in wide angle lenses is a function of the angle of view, not the focal length. The term “longer” lens is really talking about the angle of view, not the focal length, unless you’re stuck only thinking about one particular format. A 20mm full frame lens will probably have more distortion than a 16mm lens made for S16 format, even though it’s technically a “longer” focal length. But the “longer” one is actually a wide angle, while the shorter one is a normal lens for that format. It’s also a lens by lens thing, some designs are better than others, and older lenses are more likely to exhibit distortion than newer ones. 

You’re falling into the trap of thinking about focal lengths as being all the same, rather than each focal length being a design unique to the image circle it’s designed to cover. A 50mm medium format lens is very different to a 50mm made for S16. 

Try it yourself: get a wide angle lens for S16 and match the shot (same distance to subject) with a wide angle on a full frame camera and see which has more distortion. Make sure not to compare a vintage lens with a modern one. 
 

3 hours ago, Tyler Purcell said:

So to get a "wider" shot with a longer lens, one would need to increase the imager size right? 

If you’re using the same lens, and assuming the lens covers the larger format, sure. But then again, if you use more of the lens image circle, you end up seeing more of the edge distortion. So it’s possible that using the same lens to get a wider shot by moving up to a larger sensor increases the visible distortion.

 

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