The 1:1 magnification ratio means that the image of a subject projected onto the sensor (or film in this case) is the same size on the sensor as real life. For you to be able to "magnify" to a 1:1 ratio, the lens would be considered a "macro lens". Most lenses do not have a 1:1 ratio, especially IMAX lenses. In other words, if you captured an object that is 1cm in real life, and you were able to focus that object at a 1:1 ratio, that object would also be 1cm on your sensor/film (which would look gigantic / macro). If your sensor size is 35mm, and you pointed it towards a ruler, at a 1:1 magnification, it would allow you to get close enough so that your entire frame, from left to right would total 35mm in length. Hoyte loves to get intimate and close to his subjects, and he would never be able to do this with IMAX lenses, as their magnification ratios are usually not great, which is why he had custom built, 1:1 magnification "micro macro" Hasselblad's built.

Actually we did intend on getting into that deeper, but the reverse recording became another entire article and topic on its own.

Here's the short take on this: it's all about maintaining image quality. If you digitally reverse a film, you would actually get a degraded result. If you just reverse the clip in post, the way that the image has been produced with the grain and the opticals, it actually gets distorted. To avoid that, Christopher Nolan actually developed a way to reverse record the film. Which by the way, is not a new technique... he did this back in 2000 with Momento.

Hoyte van Hoytema says: "One of the biggest technical challenges was that we wanted the IMAX camera to be able to run in reverse to achieve certain in-camera physics that are not possible if the film only goes forwards."

What Hoyte was talking about was that capturing the film in reverse would be the only way you can get the most pristine image quality possible, without damaging the information of the film (if you had just reversed it in post).

This was a common in-camera special effect in the past. By reversing your film magazine, you won't need to re-print it in reverse, since every print made reduces the image quality. They needed both the reverse and forwards captured on film, in camera so that all of the footage will be of the same overall quality.

As you may know, Nolan does not like to sacrifice anything in terms of quality, and will always do things practically when he can. Hope this answers your question

100% agree with you. This wasn't really to continue the polarization of film/digital, we just thought it was really interesting to hear the difference in opinion and goals between Tarantino and Deakins. Most established cinematographers don't have this kind of polarization, some may prefer to shoot on film or digital, but they are usually open to both options as mentioned above