C700: C700 FF Aliasing

[jcs]

Can someone from Canon explain what is going on here? Observed first on MacOS in Chrome, then tested with Safari, then Windows 10/Edge (both Vimeo and YouTube):

https://www.youtube.com/watch?v=3_swZt6jTmg

00:04s in (4K, fully buffered):






Note the "canon presents" text has fine detail on curved edges and no aliasing (inserted in post, so no camera artifacts related to resolution/sampling, not likely compression related). Why are the power lines aliasing?

Here I tested the 5D3 (H.264, internal) years ago and aliasing was very minimal, even with challenging high frequency content:

https://www.youtube.com/watch?v=qkFmhKoUEv4

Given the 5.9K C700 FF sensor outputing 4K (past the 5.7K (3840/.67) threshold to be able to be alias-free), I'd expect nearly alias-free results with 4K 'Nyquist-limit' level of real detail.

 

[AndreeOnline]

I'm guessing it isn't there in the original footage. Perhaps some unfortunate post sharpening, or the result of sub-optimal export settings.

Aliasing largely went away with the 5D mkIII and hasn't really been an issue since.

 

[johnniebutters]

That was possibly the worst "Short Film" I've ever seen. The inside shots are graded so bad! Also your first screengrab is color fringing not anti aliasing which is lens based and not the camera.

Nothing in this film showcases the power of the C700 FF. You can get the same results with a C200 and spend a lot less.

 

[AndreeOnline]

Nothing in this film showcases the power of the C700 FF.

Isn't that the thing, though? You'll never really see the true power of a camera by looking at the images—they all look the same after post (especially within a brand's own range).

To showcase the power of the C700FF you probably want to make a 'camera walk around' on set and show the crew the most important design features that will help them save time and be more consistent between cameras. Same with post: explain what production features will streamline post production to deliver consistent results, faster.

 

[jcs]

The opening shot looks soft and has aliasing at the same time, very similar to the C200 when shooting internal 2K/HD. It sounded like they were shooting everything in raw with the Codex, so we should be seeing the absolute best, highly detailed imagery possible from the C700 FF. Perhaps something happened to the raw footage for the opening shot, and they had to use the proxy footage?

The 5D3 footage I posted was heavily sharpened in post, just below the point of producing significant artifacts (there are minor artifacts visible at times). While over sharpening can produce a form of aliasing, by removing smooth gradients (the same gradients that antialising algorithms add), it won't result in the kind of aliasing shown with the power lines. First, the power lines are soft and look like 1080p scaled up, and there are gaps in pixels, which is really bad aliasing (as you'd expect from line skipping or really simple deBayering methods).

Watch the power lines for the first 7 seconds: low resolution with severe aliasing at the same time: no way that'a 5.9K with high quality deBayer and downsampling to 4K. In the tech/software world we repeat test and QA with every software revision. Larger projects get dedicated QA folks who are cool with repetitive testing, over, and over again (takes a special kind of person who can do that and not get bored). It looks like this film didn't get QA'd? The headline feature of this camera is a 5.9K oversampled to 4K sensor, and they open with highly aliased 1080p looking shot?

At 1:41, fine blonde hair is aliasing (200%, no other changes):


I wasn't looking for aliasing: the power line aliasing was so dramatic I thought it must be the browser, compression, etc. After watching again and seeing aliasing in more (higher detail) shots, something is wrong with the source footage. We shouldn't be seeing any significant aliasing given the specs.

Here's fine hair detail in 4K on YouTube, same delivery constraints of highly compressed 8-bit 420 in a web browser (Alexa LF, not even a True 4K sensor (only 4.4K!)):


From this video @1:14:
https://www.youtube.com/watch?v=twobOUE-oy4

 

[jcs]

What would a test video be without a cat? (there's also dogs, an eagle, an owl, and a rabbit). 4.4K Alexa LF (link above), from 1:27:


We've got lines and gradients in every direction- aliasing is well controlled. I would expect even better from Canon's 5.9K sensor: what happened to the footage for the C700 FF?

 

[Barry G]

You seem really interested in this. You live...what...5 miles from Canon Burbank? Why not run over there and ask to see the real footage from the camera, and maybe obsess less about youtube/vimeo compressed footage. I saw the same film projected, and on a 4k monitor at NAB and there was nothing worrying about the image in terms of aliasing. Regardless, I certainly wouldn't make any kind of assumption, or spew any FUD over something I saw on youtube...or any footage that had been graded. The only aliasing that would worry me would be something I saw on the camera files.

 

[jcs]

You seem really interested in this. You live...what...5 miles from Canon Burbank? Why not run over there and ask to see the real footage from the camera, and maybe obsess less about youtube/vimeo compressed footage. I saw the same film projected, and on a 4k monitor at NAB and there was nothing worrying about the image in terms of aliasing. Regardless, I certainly wouldn't make any kind of assumption, or spew any FUD over something I saw on youtube...or any footage that had been graded. The only aliasing that would worry me would be something I saw on the camera files.

Indeed I am very interested in this- I'm sure many other Canon customers are as well (own 80D, 5D3, 1DX II, C300 II, many Canon L lenses, flashes, WiFi dongle etc.). I've defended the C700 FF from detractors from day one. However there's something wrong with the footage posted by Canon.

Is your time valuable? I take breaks between writing code (including image-processing and camera system related projects) and doing creative projects to look at the latest in camera tech and engage with others online with what I find. Canon Burbank is 8.5 miles way, about 35 minutes in traffic right now on the weekend (they are closed on the weekends). During the week that will be 50+ minutes. Each way. Googling didn't return any hits to downloadable footage for the C700 FF? Currently downloading all samples for the Alexa 65 and LF from here: http://www.arri.com/camera/alexa/learn/alexa_sample_footage/ to examine FF(+) True 4K (Alexa 65 6.5K) and the LF (4.4K). For those wishing to examine this footage: PP CC's ARRI Raw support doesn't seem to work so far with LF footage (shows black). Resolve 15 (latest) works perfectly- fast too (10-Core Windows 10, GTX 1080).

When the 5D2 came out, many lamented the aliasing and lack of 24p. I showed we could do 24p with a high quality retime with Shake. When the 5D3 came out, many lamented the soft image. I showed that the 5D3 was pretty excellent in both low aliasing and reasonable detail with post sharpening (with the BH video linked above). First to show we could do log emulation with the 1DX II (then later how we could get much better results without doing log emulation using Filmic Skin; I sell that product and forum rules prevent me from linking to it). Now the C700 FF demo video is released and there are serious problems with the image quality. As a Canon customer, I don't think this video is helping to promote the C700 FF (for a variety of reasons), and I would certainly not be interested in buying or renting one given what they have posted. In fact, for anything with a reasonable budget this video has me looking at ARRI. I think it would be in Canon's best interest to remove that video and figure out what happened, then re-upload once it's fixed. ARRI doesn't offer DPAF or even a True 4K capable camera for sale (Alexa 65 is rental only). The 4.4K Alexa LF demos released are out performing the 5.9K C700 FF footage which should not be happening given the specs. I would expect the Alexa LF to have the edge in skin tones, DR, highlights, and slomo, which is fair given the difference in cost, and for the C700 FF to have the edge in detail without aliasing.

To call what I have posted FUD is highly unprofessional, Barry, given the years of doing everything I can to help improve the image quality of Canon camera systems. I've done the same with Sony (e.g. showing how to get decent skin tones from the A7S II), and called out ARRI when they made claims about full frame having special qualities (that don't exist). The opposite of FUD and without bias: an honest pursuit of quality and truth.

I look forward to hearing what Canon has to say about this issue, and seeing pristine alias-free True 4K footage from the C700 FF, including examining footage provided by Canon for download.

 

[indiawilds]

You seem really interested in this. You live...what...5 miles from Canon Burbank? Why not run over there and ask to see the real footage from the camera, and maybe obsess less about youtube/vimeo compressed footage. I saw the same film projected, and on a 4k monitor at NAB and there was nothing worrying about the image in terms of aliasing. Regardless, I certainly wouldn't make any kind of assumption, or spew any FUD over something I saw on youtube...or any footage that had been graded. The only aliasing that would worry me would be something I saw on the camera files.

Great to know this. As on friday I was told by Canon that the C700FF will only be available in end july/august in my country. So getting one to see soon is something out of question for us at the moment. So I was wanting to know about handson experiences (in another thread). You guys are lucky to see stuff in 4K monitors. Here we see canon events projecting stuff in screens not meant for films.

I just want to see the difference between the same shot using codex and internal recording in the C700 FF. At the moment buying is out of question. However, very keen to use in OK budget commercials.

Got to finally touch the Canon ME20FSH with the 4Million ISO sensor. That was wow. If I were not busy now, then I would have just pulled it for a spin shooting some wildlife.

PS: As far as getting the source footage to examine, I am sure Canon USA reps can help. May be messaging them here in the forum/twitter/email can lead somewhere?

 

[jcs]

Here's the other 6K => 4K FF camera joining the party: http://www.dvxuser.com/V6/showthrea...essive-Skin-Tones&p=1986752604#post1986752604
No visible aliasing and excellent skin tones. More importantly, this low budget shoot really shows what the camera can do: this video will get at least 10x more positive feedback (hint). Fortunately for Canon I don't own any Sony lenses anymore and the VENICE doesn't have DPAF.

Gotta say these new FF 4K cinema cameras are looking impressive. Looking forward to new (alias-free) demos for the C700 FF!

 

[Barry G]

Indeed I am very interested in this- I'm sure many other Canon customers are as well (own 80D, 5D3, 1DX II, C300 II, many Canon L lenses, flashes, WiFi dongle etc.). I've defended the C700 FF from detractors from day one. However there's something wrong with the footage posted by Canon.

Is your time valuable? I take breaks between writing code (including image-processing and camera system related projects) and doing creative projects to look at the latest in camera tech and engage with others online with what I find. Canon Burbank is 8.5 miles way, about 35 minutes in traffic right now on the weekend (they are closed on the weekends). During the week that will be 50+ minutes. Each way. Googling didn't return any hits to downloadable footage for the C700 FF? Currently downloading all samples for the Alexa 65 and LF from here: http://www.arri.com/camera/alexa/learn/alexa_sample_footage/ to examine FF(+) True 4K (Alexa 65 6.5K) and the LF (4.4K). For those wishing to examine this footage: PP CC's ARRI Raw support doesn't seem to work so far with LF footage (shows black). Resolve 15 (latest) works perfectly- fast too (10-Core Windows 10, GTX 1080).

When the 5D2 came out, many lamented the aliasing and lack of 24p. I showed we could do 24p with a high quality retime with Shake. When the 5D3 came out, many lamented the soft image. I showed that the 5D3 was pretty excellent in both low aliasing and reasonable detail with post sharpening (with the BH video linked above). First to show we could do log emulation with the 1DX II (then later how we could get much better results without doing log emulation using Filmic Skin; I sell that product and forum rules prevent me from linking to it). Now the C700 FF demo video is released and there are serious problems with the image quality. As a Canon customer, I don't think this video is helping to promote the C700 FF (for a variety of reasons), and I would certainly not be interested in buying or renting one given what they have posted. In fact, for anything with a reasonable budget this video has me looking at ARRI. I think it would be in Canon's best interest to remove that video and figure out what happened, then re-upload once it's fixed. ARRI doesn't offer DPAF or even a True 4K capable camera for sale (Alexa 65 is rental only). The 4.4K Alexa LF demos released are out performing the 5.9K C700 FF footage which should not be happening given the specs. I would expect the Alexa LF to have the edge in skin tones, DR, highlights, and slomo, which is fair given the difference in cost, and for the C700 FF to have the edge in detail without aliasing.

To call what I have posted FUD is highly unprofessional, Barry, given the years of doing everything I can to help improve the image quality of Canon camera systems. I've done the same with Sony (e.g. showing how to get decent skin tones from the A7S II), and called out ARRI when they made claims about full frame having special qualities (that don't exist). The opposite of FUD and without bias: an honest pursuit of quality and truth.

I look forward to hearing what Canon has to say about this issue, and seeing pristine alias-free True 4K footage from the C700 FF, including examining footage provided by Canon for download.

ok....so Here's what you said (bold emphasis mine) "I wasn't looking for aliasing: the power line aliasing was so dramatic I thought it must be the browser, compression, etc. After watching again and seeing aliasing in more (higher detail) shots, something is wrong with the source footage."

This my friend is something that you cannot know from watching a 1080 clip on youtube, a 4k compressed clip on vimeo, and certainly anything that's been graded. That's all I'm saying. When you say "something is wrong with the source footage" that...is FUD, when you don't really have evidence of said.

Codex has uploaded the same film to their vimeo. It seems to be missing something. So either they managed to fix the source footage, or it was in the grading or encoding as I and others have said was most likely. And you can download it from their page.

https://vimeo.com/263635679

 

[jcs]

ok....so Here's what you said (bold emphasis mine) "I wasn't looking for aliasing: the power line aliasing was so dramatic I thought it must be the browser, compression, etc. After watching again and seeing aliasing in more (higher detail) shots, something is wrong with the source footage."

This my friend is something that you cannot know from watching a 1080 clip on youtube, a 4k compressed clip on vimeo, and certainly anything that's been graded. That's all I'm saying. When you say "something is wrong with the source footage" that...is FUD, when you don't really have evidence of said.

Codex has uploaded the same film to their vimeo. It seems to be missing something. So either they managed to fix the source footage, or it was in the grading or encoding as I and others have said was most likely. And you can download it from their page.

https://vimeo.com/263635679

Well my friend I see you've referred to one of my posts on Vimeo regarding fixing the LUTs for the C300 II, so I hope you see my intentions are to help / solve problems rather than spread FUD, which is not helpful.

Thanks for the tip to Codex's version. I downloaded the original and found the hair at 1:41 wasn't aliasing. I checked on the Vimeo playback at 4K and still no aliasing. Next I checked Canon's version on Vimeo in 4K. Both versions will go through Vimeo's backend transcode system (ffmpeg-based) so the only difference when viewed on the web will be source footage differences. Here are the results (frames matched at around 1:37):

Codex version:


Canon version:


It's clear the source footage (original footage they uploaded) is different. The Canon footage reminds me of C300 II footage, which aliases. And I do admit, when I first saw aliasing on the C300 II I was very disappointed. Only later after doing the math/analysis did I realize the C300 II 4K sensor is not sufficient to provide Nyquist Limit / alias-free True 4K footage. The C300 II is still a great camera and overall it has more + than -. So when the C700 FF was announced with a 5.9K sensor, I (and I'm sure many others who understand what True 4K means) was excited to see a Canon camera with DPAF and decent color science along with True 4K. Imagine the dismay for the opening shot with horrible aliasing, similar to 5D Mark II level, on the power lines. Surely this must be a mistake, browser, compressor etc. After checking other similar 4K cameras on the same platforms and thus going through the same transcode systems, it became clear something was wrong with the source footage.

Thanks to your help, it's clear that indeed, something is wrong with Canon's footage. The Codex version on Vimeo still has an aliasing pattern on the power lines, yet it doesn't dance around and look nearly as bad as Canon's footage on Vimeo. The Codex downloaded original also has the 'fixed alias looking patterns' on the power lines. Either the power lines just look like that in real life (dirt/weather for one set of lines, twisted cables on another?), or it's some kind of aliasing artifact. Shooting with another camera system in the same conditions can help tell the difference. puredrifting shot a test chart (hopefully 4K resolution chart in addition to color), so perhaps that will help provide a better understanding of the camera's true performance capability with respect to resolution and aliasing.

The question is what happened to Canon's footage that they uploaded to Vimeo (and YouTube)? Clearly the Codex version is better going through the same transcode process: no significant visible aliasing on the hair and no dancing aliasing on the power lines. 'no significant' aliasing: looking more closely at the areas on the Codex version where Canon's footage is aliasing, there's subtle black areas which look like "almost aliasing". Which is quite a bit different from the included Alexa LF footage in this thread which doesn't have these kinds of patterns in thin hairs.

Would love to see a simple demo as with the Sony VENICE and Alexa LF with slow/no camera motion on faces/skin tones, and high detail subjects. See the VENICE thread I referenced to see the VENICE in Venice Italy demo. Specifically the ultra high detail costumes, brick walls, etc. They shot mostly deep DOF and some shots look truly incredible with both near and far (at the limit) in focus along with amazing dynamic range (sun in shot or just behind subject). I looked intently to find any artifacts or aliasing, even minor pixel dancing: found nothing (YouTube compression for 4K is pretty good). This kind of demo would also be helpful for the C700 FF, and then go one further and show DPAF tracking subjects that would be impossible/very-hard with a manual focus puller. The boxing demo shows good low light performance, however highlight/DR performance doesn't seem to be at the same level as the Alexa LF or Sony VENICE (didn't notice blown highlights (yet) in their demos as with the boxing hair screen shot). Comparing all cameras in the same conditions would be the most fair way to compare, though I'd expect both the VENICE and Alexa LF to perform better given the higher cost. Not clear how the Canon lenses which can use DPAF compare to the new Leica Thalia lenses (full manual): that may be one of the reasons the VENICE shots look so detailed (real detail, no artifacts: not over-sharpened) and "3D", from http://cw-sonderoptic.com/leica-thalia/ :

Images captured with the Leica Thalia lenses can appear to have an added depth and dimensionality, especially on larger sensors, due to a gradual focus fall off curve. Rather than even, flat layers of focus across the frame, the Thalia lenses have a slight curve that can make an image “pop” because it is simultaneously more consistent with human vision and yet different from most images created with modern lenses.

Using the PL mount, Thalia lenses can of course be used with the C700 FF (manual only).