A "real" 4k from a 5k - 6k camera

[Joe G.]

Much has been said about how the 4k from a Red One is "effectively" a 3.2K or some even say 2.5K "effective" resolution. Is there a white paper that puts this into a coherent explanation?

So, at what point do these new cameras become an "effective" or a "real" 4K image?

What determines the actual resolution?

How can these 5 or 6K images be turned into real 4K quality images suitable for the big screen and a high end 4k post production workflow?

When will we learn more about this workflow, which at the moment seems non-existent?

[Andrew Walker]

Much has been said about how the 4k from a Red One is "effectively" a 3.2K or some even say 2.5K "effective" resolution. Is there a white paper that puts this into a coherent explanation?

So, at what point do these new cameras become an "effective" or a "real" 4K image?

What determines the actual resolution?

How can these 5 or 6K images be turned into real 4K quality images suitable for the big screen and a high end 4k post production workflow?

When will we learn more about this workflow, which at the moment seems non-existent?

The Red One is already suitable for the big screen. At least what I've seen on the big screen at Warner Bros. Both on film and digital.

[Jannard]

The highest measured "real resolution" of 35mm film is 3.2K. And that is slow film. ISO 500 film is under 3K. Just for your reference...

Jim

[Ryan Patch]

Effective resolution is measured by the resolution that can be "resolved" from details on screen, like a camera test chart with small details.

Your post seems to be putting 4k at the gold standard of what you think is suitable for the big screen. Remember that Star Wars was shot at 1080, and Lord of the Rings was scanned, DI'd and printed back at 2k.

When you say that you want a workflow for a "real" 4k image, you're saying that you want a workflow for 5k or 6k, right? The answer is... probably when a) cameras are released to the public that image at 5, 6, etc., and b) when you make it happen. If you want workflow that is set in stone and everyone knows how it's supported through and through, go shoot some film. If you're going to pick up a device that is brand new, is rewriting several rules, less than a year after the first models are released, you're going to have to accept some of the growing pains.

And, practically, the workflow looks like...

Edit with proxy files, conform and color with a 5, 6, 9k master, then render out 4k images.

[Ryan Patch]

Also, this should tell you some more about resolution, etc. Keep in mind it's written by some people with an agenda, though, just as we, here, have an agenda.

http://www.arri.com/entry/4kplus-systems.htm

Ryan

[Graeme Nattress]

Effective resolution is the measured resolution. That means pointing your camera at a test chart, and reading off the result. However, in reality it's more complex than that.

Many "HD" camera systems are so desperate to appear sharp and detailed that they do not adequately filter out the detail that lies above which the camera can record. At RED, we're a bit conservative with our filtering. We want to ensure that you don't get any false details, or aliases appearing in your images. There are a number of reasons why this is important, not least how these false details can increase the perception of motion judder, make it harder to compress for broadcast or distribution via a motion adaptive codec, or just plain look ugly.

Instead, with RED, you get a more natural level of detail, not forced, that looks to me more how the eye sees things.

Graeme

[Tico Llaurador]

Instead, with RED, you get a more natural level of detail, not forced, that looks to me more how the eye sees things.

Graeme

And *THAT* is exactly why I love the look of images produced by the RED One. They have a very "organic" feel to them.

[Graeme Nattress]

Correct answer Tico!

Graeme

[David Mullen ASC]

Trouble is that it is hard to quantify sharpness in relation to aliasing, because how much aliasing you want to accept in order to gain the impression of more sharpness is a judgement call on the part of the camera designer.

Simply telling you the number of lines resolved, or the MTF of the system, etc. doesn't give you the whole picture, so to speak, in regards to sharpness, detail, resolution, and the perception of those things (and perception is a valid thing to consider). Which is why opinions can vary so much, and why you should shoot your own tests and make your own judgments.

The real problem with this whole 4K resolution benchmark, while a theoretical ideal, is that there really isn't a real world example to compare against. You'd almost want to design a test image shot with a 4K monochrome sensor in three passes filtered red, green, blue as some sort of digital 4K RGB standard to measure all movie cameras against. But even then, you'd have to decide how much aliasing to accept in the system.

I'm not sure there really is a simple engineering figure or measurement that can sum up the whole picture regarding resolution.

I'm not sure studying single frames either is a completely accurate picture since detail on film lies on different grains on each frame, and our eye averages information of a couple of frames during projection. Some people use the term "temporal resolution" to describe some of the effects of shooting and projecting at higher frame rates, though I'm not sure if that's a real engineering concept.

I think many of us can agree that what we want is an image containing a lot of fine details without aliasing artifacts and without the impression of artificial sharpening tricks. One way to get that is by oversampling, hence why 70mm and IMAX photography looks so nice -- lot of fine detail, low grain, but not edgy-looking. So larger sensors with more photosites will help in this regards.

[Graeme Nattress]

David, with answers like that you're putting me out of a job!

Graeme