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June 17, 2018 4:24 AM Subscribe
A Clear Look at the Issue of Resolution
#BoringFilmTechStuff: "Under the #BoringFilmTechStuff hashtag on Twitter, I’ve been making available a series of technical posts that I thought might be useful or interesting to other filmmakers."
Replies To Some Inquiries About The Resolution Demo
Big K 2014: Why We Don't Need 4k TVs
A Reluctant Quantification Of Megapixels
Viewing RAW On Set
On Color Science: An Intro For Filmmakers
On Film Grain Emulation
Steve Yedlin, ASC [previously] offers an intriguing demonstration on how capture formats, pixel counts and postproduction techniques affect image quality and why simply counting Ks is not a solution when selecting a camera.
#BoringFilmTechStuff: "Under the #BoringFilmTechStuff hashtag on Twitter, I’ve been making available a series of technical posts that I thought might be useful or interesting to other filmmakers."
Replies To Some Inquiries About The Resolution Demo
Big K 2014: Why We Don't Need 4k TVs
A Reluctant Quantification Of Megapixels
Viewing RAW On Set
On Color Science: An Intro For Filmmakers
On Film Grain Emulation
Even compressed I apparently lack the bandwidth to watch that.
posted by adam hominem at 9:21 AM on June 17, 2018
posted by adam hominem at 9:21 AM on June 17, 2018
I'm obviously way outta my league here but I don't understand how to agree with very much he says in the Why We Don't Need 4K TVs link. Something like the "Peru 8K" video on my TCL 55R615 is jaw-droppingly stunning compared to watching it in 1080p, yet he writes:
posted by glonous keming at 10:58 AM on June 17, 2018 [5 favorites]
The truth is that given a fair comparison with controlled variables, 4k resolution is nearly indistinguishable (or perhaps completely indistinguishable) from HD TV resolution in normal viewing conditions, and the TV manufacturers are in large part selling snake oil to consumers.Maybe that was more true in 2014 when he penned it, and maybe I'm completely missing his point here, but I mean... Come over to my house and I can show you some really damn good-looking snake oil, I guess?
posted by glonous keming at 10:58 AM on June 17, 2018 [5 favorites]
Are you sitting so close to your screen that you can actually perceive your display's pixels? If yes then HD isn't enough. But I very much doubt that the differences you're seeing are exclusively or even mainly due to your screen's pixel density, though. Remember that HDR has nothing to do with 4k.
The only way you could meaningfully compare between 1080p and 4k would be to man-in-the-middle the decompressed 4k video data being sent to your display, pass it through a 4k > 1080p > back to 4k (important!) loop using best practices, and only then feed it to the display.
If you're just picking YouTube's 1080p and 4k options and using that as a basis, you might be doing the video equivalent of comparing a decently mastered SACD to a hypercompressed CD master and claiming that Redbook audio just don't cut it. There's way too many variables you're not controlling for, making the comparison meaningless.
If you're sceptical and haven't done so, watch the second demonstration video in a 1080p display (or in your 4k screen with 1:1 pixel mapping and sit even closer to compensate).
posted by Bangaioh at 12:01 PM on June 17, 2018 [1 favorite]
The only way you could meaningfully compare between 1080p and 4k would be to man-in-the-middle the decompressed 4k video data being sent to your display, pass it through a 4k > 1080p > back to 4k (important!) loop using best practices, and only then feed it to the display.
If you're just picking YouTube's 1080p and 4k options and using that as a basis, you might be doing the video equivalent of comparing a decently mastered SACD to a hypercompressed CD master and claiming that Redbook audio just don't cut it. There's way too many variables you're not controlling for, making the comparison meaningless.
If you're sceptical and haven't done so, watch the second demonstration video in a 1080p display (or in your 4k screen with 1:1 pixel mapping and sit even closer to compensate).
posted by Bangaioh at 12:01 PM on June 17, 2018 [1 favorite]
But I very much doubt that the differences you're seeing are exclusively or even mainly due to your screen's pixel density, though.
You're not going to get an OLED TV at 1080p, so - if you want to cover the majority of the color gamut at a gloriously high bit-depth, 4k is the way to go. So, kind of yes? There's really no way to get the image quality of a 4k display at 1080 resolutions, so it's not really worth discussing - those displays are just fundamentally better at display color.
I *really* don't want to bother with the math right now, but I'm going to guess that yes, there is a real discernible difference between 4k and 1080p (or not a good one). Visual Acuity is a start. It boils down to the physical size of the pixels (which is a little hand-wavey since they're not distinct blocks of light, but you can reasonably approximate since we can't resolve the individual LED elements without a magnifying glass) - which varies on the size of the TV (or whatever your display is), and then take into account the viewing distance (Human Eyesight and 4k viewing). On the whole: the talk is kind of bullshit*, but they have an interesting point re: processing done to get to the final image/image capture limitations - but those are kind of... obvious (of course my cellphone is going to take crappy, crappy photos compared to my old-ish DSLR, even at nearly the same resolution).
posted by combinatorial explosion at 2:43 PM on June 17, 2018
You're not going to get an OLED TV at 1080p, so - if you want to cover the majority of the color gamut at a gloriously high bit-depth, 4k is the way to go. So, kind of yes? There's really no way to get the image quality of a 4k display at 1080 resolutions, so it's not really worth discussing - those displays are just fundamentally better at display color.
I *really* don't want to bother with the math right now, but I'm going to guess that yes, there is a real discernible difference between 4k and 1080p (or not a good one). Visual Acuity is a start. It boils down to the physical size of the pixels (which is a little hand-wavey since they're not distinct blocks of light, but you can reasonably approximate since we can't resolve the individual LED elements without a magnifying glass) - which varies on the size of the TV (or whatever your display is), and then take into account the viewing distance (Human Eyesight and 4k viewing). On the whole: the talk is kind of bullshit*, but they have an interesting point re: processing done to get to the final image/image capture limitations - but those are kind of... obvious (of course my cellphone is going to take crappy, crappy photos compared to my old-ish DSLR, even at nearly the same resolution).
posted by combinatorial explosion at 2:43 PM on June 17, 2018
4K TVs might be somewhat pointless unless the screen is enormous, but the 4K format has a use-case for 360 degree video (and even then, it's not quite enough). You can always use more pixels!
I'm still a little skeptical of claims that 4K (12.6 megapixels) is "enough" though. Just using film as a baseline, I've read figures in 10-100 MP range as the "effective resolution" of average quality 35mm film (obviously there's no exact number but Wikipedia says 33.6 MP). Why would we stop improving digital image quality when it's still short of the resolving power of its analog equivalent?
posted by L.P. Hatecraft at 4:04 PM on June 17, 2018
I'm still a little skeptical of claims that 4K (12.6 megapixels) is "enough" though. Just using film as a baseline, I've read figures in 10-100 MP range as the "effective resolution" of average quality 35mm film (obviously there's no exact number but Wikipedia says 33.6 MP). Why would we stop improving digital image quality when it's still short of the resolving power of its analog equivalent?
posted by L.P. Hatecraft at 4:04 PM on June 17, 2018
4K has done two things for us:
Cheap, hi res monitors (we were stuck at 1080p for SO! Long!)
The format fiddling has gotten manufacturers to finally take dynamic range a little bit seriously.
posted by wotsac at 4:09 PM on June 17, 2018 [1 favorite]
Cheap, hi res monitors (we were stuck at 1080p for SO! Long!)
The format fiddling has gotten manufacturers to finally take dynamic range a little bit seriously.
posted by wotsac at 4:09 PM on June 17, 2018 [1 favorite]
The format fiddling has gotten manufacturers to finally take dynamic range a little bit seriously.
Plus it’s given them a whole new slew of ways to make the default settings look like absolute garbage.
posted by Sys Rq at 4:43 PM on June 17, 2018 [1 favorite]
Plus it’s given them a whole new slew of ways to make the default settings look like absolute garbage.
posted by Sys Rq at 4:43 PM on June 17, 2018 [1 favorite]
There is a definite visible improvement in detail and quality moving from 1080p to 4k, but only if you have a ridiculously large TV or sit closer than most people do. That's why 4k screens and monitors for computing devices are inarguably better.
I have a 4k TV in my bedroom and have been considering one for the living room, but got pretty discouraged when I realized I'd need at least a 75" (more likely 85") set to get the same experience. Basically, for the moment if you sit farther than 6-8' from your set, large sums are required to buy one large enough to make 4k on its own worth doing.
HDR, obviously, depends more on your lighting than the viewing distance, but it can be quite impressive in a dimly lit room even at larger viewing distances.
posted by wierdo at 7:27 PM on June 17, 2018
I have a 4k TV in my bedroom and have been considering one for the living room, but got pretty discouraged when I realized I'd need at least a 75" (more likely 85") set to get the same experience. Basically, for the moment if you sit farther than 6-8' from your set, large sums are required to buy one large enough to make 4k on its own worth doing.
HDR, obviously, depends more on your lighting than the viewing distance, but it can be quite impressive in a dimly lit room even at larger viewing distances.
posted by wierdo at 7:27 PM on June 17, 2018
Call me when 4k projectors are reasonably priced.
posted by grumpybear69 at 8:26 PM on June 17, 2018 [1 favorite]
posted by grumpybear69 at 8:26 PM on June 17, 2018 [1 favorite]
Why would we stop improving digital image quality when it's still short of the resolving power of its analog equivalent?
Because analog image quality is itself scaleable, and can get well over 500 megapixels if you want.
I recently got a DF with the D4 sensor, which is a full frame at 16 megapixels. So low pixel count but (relatively) large photosites, and I really love the image quality! The grain at high ISOs is way better than my 5D MKIII, and while I've got better EF lenses I'm going to build up my F mount collection because I really like this (lower resolution) sensor.
posted by weed donkey at 9:59 PM on June 17, 2018
Because analog image quality is itself scaleable, and can get well over 500 megapixels if you want.
I recently got a DF with the D4 sensor, which is a full frame at 16 megapixels. So low pixel count but (relatively) large photosites, and I really love the image quality! The grain at high ISOs is way better than my 5D MKIII, and while I've got better EF lenses I'm going to build up my F mount collection because I really like this (lower resolution) sensor.
posted by weed donkey at 9:59 PM on June 17, 2018
Thanks for posting, the second video in the link is fantastic -- for as far it goes. Yedlin's premise of showing that only focusing on resolution as a metric for evaluating quality in cinema viewing is right on. And his supporting presentation is excellent. However a few things have changed since he wrote this article and video:
As storage costs keep dropping and workflow speeds keep increasing, capturing and working with 8K images in post production has become straightforward. But don't confuse resolution with sharpness. Using 8K files doesn’t necessarily mean showing every pore on an actor’s skin or, as Yedlin shows, trying to get more visual acuity in cinema playback. Many DPs actually use diffusion filters or softer lenses, e.g., the lovely new Cooke S7 primes, when capturing at 8K.
What higher resolution does give one is an expanded toolkit, e.g., the ability to fine tune framing in post and the ability to stabilize shots. Capturing at 8K and delivering at a lower resolution allows both of those to happen with no loss of resolution in the delivery so that the processed shots exactly match the unprocessed shots. David Fincher uses both of these extensively to keep the audience focused on exactly the part of the screen he wants. They're also super useful for indy filmmakers who had to work with limited time on set and therefore need to correct / fine tune shots. And high resolution has obvious benefits for all VFX work from simple green screen composites to complex CGI integration with live action.
But -- as they say -- it's the quality of the pixels not the quantity of pixels that determine how good an image looks. The reality is that as of June 2018 capture and post at high rez generally means trading off colorimetry for resolution: the RED cameras shoot the highest resolution but the Arri Alexas have much better color fidelity and people look much more attractive when captured with Alexa. The effect of High Dynamic Range on image quality is even larger. If you ever have a chance to see a true HDR film in a Dolby theater don't miss it -- guarantee you'll be blown away. Unfortunately we're still a bit away from perfecting how to master in both HDR and SDR and standardizing displaying it in consumer's homes.
Lastly, on the subject of compression. With all due respect to Yedlin, compression algorithms are very much affected by resolution regardless of playback resolution. To demonstrate, take something that has a lot of changes from frame to frame, e.g., an abstract video art piece or some very grainy material. Post them at 4K and 2K to Vimeo or YouTube and play them back at 2K or lower. The post that came from the 4K source will have far fewer artifacts and look much better.
Anyway, these are relatively nit picks to Yedlin's excellent work. Tnx again for posting!
posted by Dean358 at 5:43 AM on June 18, 2018 [1 favorite]
As storage costs keep dropping and workflow speeds keep increasing, capturing and working with 8K images in post production has become straightforward. But don't confuse resolution with sharpness. Using 8K files doesn’t necessarily mean showing every pore on an actor’s skin or, as Yedlin shows, trying to get more visual acuity in cinema playback. Many DPs actually use diffusion filters or softer lenses, e.g., the lovely new Cooke S7 primes, when capturing at 8K.
What higher resolution does give one is an expanded toolkit, e.g., the ability to fine tune framing in post and the ability to stabilize shots. Capturing at 8K and delivering at a lower resolution allows both of those to happen with no loss of resolution in the delivery so that the processed shots exactly match the unprocessed shots. David Fincher uses both of these extensively to keep the audience focused on exactly the part of the screen he wants. They're also super useful for indy filmmakers who had to work with limited time on set and therefore need to correct / fine tune shots. And high resolution has obvious benefits for all VFX work from simple green screen composites to complex CGI integration with live action.
But -- as they say -- it's the quality of the pixels not the quantity of pixels that determine how good an image looks. The reality is that as of June 2018 capture and post at high rez generally means trading off colorimetry for resolution: the RED cameras shoot the highest resolution but the Arri Alexas have much better color fidelity and people look much more attractive when captured with Alexa. The effect of High Dynamic Range on image quality is even larger. If you ever have a chance to see a true HDR film in a Dolby theater don't miss it -- guarantee you'll be blown away. Unfortunately we're still a bit away from perfecting how to master in both HDR and SDR and standardizing displaying it in consumer's homes.
Lastly, on the subject of compression. With all due respect to Yedlin, compression algorithms are very much affected by resolution regardless of playback resolution. To demonstrate, take something that has a lot of changes from frame to frame, e.g., an abstract video art piece or some very grainy material. Post them at 4K and 2K to Vimeo or YouTube and play them back at 2K or lower. The post that came from the 4K source will have far fewer artifacts and look much better.
Anyway, these are relatively nit picks to Yedlin's excellent work. Tnx again for posting!
posted by Dean358 at 5:43 AM on June 18, 2018 [1 favorite]
To follow up my earlier post, I finally had time to sit and watch both parts of the resolution demo. As a result, I have a better understanding of Yedlin's meaning.
And I moved my couch a foot and a half closer to my tv.
posted by glonous keming at 8:00 PM on June 18, 2018
And I moved my couch a foot and a half closer to my tv.
posted by glonous keming at 8:00 PM on June 18, 2018
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Despite being targeted to cinematographers and other industry professionals I found it accessible and interesting enough for a wider audience.
posted by Bangaioh at 4:28 AM on June 17, 2018 [1 favorite]