What does imax mean (95% IMAX cinemas are rubbish)

At present, the two most popular movies are 800 at home and Tenet abroad.

In addition to being expected to revitalize the cinema, they also have one thing in common, that is, the whole film was shot with IMAX camera.

What is IMAX?

IMAX, the abbreviation of Image Maximum, literally translates as image maximization.

But is IMAX really just big?

Of course not, it represents a whole system from shooting to screening. Even if it's big, it's different. The films shot by different cameras and shown in different theaters are much worse.

For example, there are so many versions of Dunkirk, among which there are only three IMAX versions.

So even if you buy a ticket for IMAX, it may not bring you the best experience.

To get the best viewing experience, we have to start with the shooting and screening of IMAX.

Before talking about IMAX cameras and cinemas, we need to define a concept, that is, frame.

1 framework

What is a picture?

Frame refers to the imaging area of the film. The corresponding digital camera refers to the size of the sensor (photosensitive element).

In film, the size of the imaging area (frame size) is determined by the size of the selected film and the length of the film used.

Common film sizes are divided into 16mm, 35mm and 65mm according to the film width.

The film length occupied by a single picture is generally expressed by the number of perforations (small holes distributed on both sides of the film).

For example, the mainstream wide-screen commercial films at present all use 35mm 4 perforated frames.

This means that the picture size is about 24x10.35mm, and the frame ratio is 2.40: 1 (the aspect ratio of the picture).

The world's largest IMAX film camera uses 65mm film for horizontal shooting. The length of a single frame reaches 15 perforations, the actual frame is about 70x48.5mm, and the frame ratio can reach 1.43: 1. This special frame version is usually called "70mm IMAX 15 perforation".

(The picture above is a direct comparison of various common picture frames. )

Generally speaking, when other parameters are the same, the larger the frame of the film (the area of the photosensitive element), the more details of the recorded picture, and the better the picture quality.

The above knowledge sounds a bit circuitous, but it is very important. Only by understanding the framework can we have an accurate grasp of different formats of movies.

2 IMAX cameras

Next, let's talk about IMAX cameras.

Although both Babai and Tenet claim to shoot with IMAX cameras, they use different kinds of cameras.

The first is the IMAX 70mm film camera mentioned above.

There are only a few such machines in the world. Nolan smashed one while filming The Dark Knight, and then smashed another while filming The Rise of the Dark Knight.

Although this machine is large, expensive and noisy, its advantage is that it can shoot a very large negative (70x48.5mm), with a frame rate of 1.43 and an equivalent resolution of 8K~ 18K. This is what Tenet used.

The second is the Arri Alexa 65 IMAX digital camera.

This is a co-branded version specially made by Alei Company for IMAX movies based on the original ALEXA 65 camera.

The sensor size of the original machine is roughly equivalent to 65mm 5-hole film, which is almost the limit that digital cameras can reach at present. The effective frame is about 54. 12x25.58mm, and the original frame ratio is 2. 1 1: 1.

The joint version is a version of 1.90: 1 specially designed for IMAX movies based on the original version, with a resolution of about 6K.

This is the mainstream IMAX camera at present. It is only for rent and not for sale. Like "Reunion 3", 800 uses this kind.

Let's make an intuitive comparison, taking Nolan's movies as an example, and see how much more the IMAX version with the largest frame is than the non-IMAX version with the size of 2.40: 1.

The Dark Knight

Dunkirk.

The larger the original frame of a movie, the larger the cinema screen needed to show this kind of movie.

Seeing this, some people may ask, if I scale these large-format original movies, can they be shown in ordinary cinemas?

Yes, it can, but it's different from putting a Ferrari engine on a tractor.

3 IMAX cinema

Let's talk about the cinema.

At present, IMAX cinemas are divided into four categories.

IMAX Cinema Hall (IMAX 70mm), Digital Hall (IMAX Xenon), Laser Hall (IMAX GT with laser) and New Generation Laser Hall (IMAX with laser).

There are almost no movie halls (IMAX 70mm) in China, and only a few science and technology museums are only used to show popular science films and are not used for commercial purposes.

Like film cameras, this kind of hall will only become less and less in the future. After all, movies are slowly retreating from the historical stage.

xenon lamp

More than 95% of the total IMAX halls in China are a set of digital IMAX system introduced by IMAX Company in 2008, which uses xenon lamps for projection.

But the highest resolution it can display is only 2K, which is often called pseudo IMAX.

15 years, in order to make up for the criticism of digital IMAX, IMAX company introduced the laser version of IMAX(IMAX GT with Laser), which was projected by two 4K laser machines and equipped with a brand-new 12 channel sound system to stop Dolby.

Most importantly, its screen aspect ratio can reach 1.3 (different theaters have differences), and it works very well when showing IMAX movies with the frame ratio of 1.43: 1, and the resolution is improved to 4K compared with ordinary digital halls.

So watch some Nolan movies. Apart from the cinema, this is the best hall in existence.

But in the mainland, the number of IMAX laser halls is also pitiful, only six * * *. (see above)

The last one is IMAX with Laser, which is projected by a two-mirror 4K laser.

The screen and venue of the original general digital hall 1.77: 1 can be used, so the image quality is improved and the reconstruction cost is not high. Mainly developed by IMAX company, it iterates a large number of general digital halls (IMAX Xenon).

To sum up, in terms of screen size,

The screen width of the digital hall is between 14m-25m, the height is between 7m- 14m, and the aspect ratio of the screen is ≈ 1.77: 1.

The screen width of the laser hall is 23m-32m, the height is 17m-2 1m, and the aspect ratio of the screen is ≈ 1.3: 1.

The screen of the new generation laser hall is similar to the digital hall, with a width of 16m-25m, a height of 8m- 14m and an aspect ratio of 1.77: 1.

At present, IMAX Company only shows IMAX movies in the format of 1.43: 1 in the laser hall, and the other two halls only show the version of 1.80: 1 cut out on this basis.

Therefore, apart from the rarely seen IMAX movie hall, among the other three halls, if you want to experience a complete IMAX movie in 1.43: 1 format, such as the upcoming Tenet, the laser hall is the best choice at present.

Although ordinary digital halls are common, the experience is the worst (limited to the horizontal comparison of various IMAX halls).

And if there is no laser hall in your city, and you watch 800 or something like "Tang Tan 3" or later, it is actually a good choice to go to the new generation laser hall.

Because they used Alexa 65 IMAX digital camera when shooting, the original film of 1.90: 1 was almost full on the screen of 1.77: 1, and they could see 26 more contents than the 2.39: 1 version shown in non-IMAX cinemas.

And the resolution, brightness and contrast of the new generation laser museum far exceed those of the ordinary digital museum.

Although there are not many such halls, you can still find them. You can search IMAX China on Wikipedia. It's all listed above.

Finally, although there is an IMAX version of "Leap" released in Mulan later, it was not shot with an IMAX camera, but with a digital reproduction technology called IMAX DMR.

So their IMAX version is only scaled and improved in size, and there will be no more picture content than the normal version.