Nikon Z RAW video support

[Super8]

3 hours ago, Falk Lumo said:

Dear fellow readers. The above posting by Super8 is defamatory. Therefore, I can't ignore the troll. I hope moderators take notice.

Let's put some facts straight for everybody to see:

• All information is in my blog post article. It contains all necessary details to reproduce, or falsify, my findings. It follows a scientific protocol.
• Super8 decided to ignore all this information and rather cite an early attempt - quickly dismissed - as visible in a public Youtube comment section. My cooperation with Marc mostly happened via email in private communication. Of course, in the very beginning, Marc had to learn a thing or two. Rather normal. I can only assume that Super8 deliberately tries to run a FUD attack against my findings. That's sad. If you don't like it, just run your own test. Then we'll talk.
• The printed test chart was never used to produce my result. Actually, I dismissed it for obvious reasons. Showing it here is nothing but trolling.

Nevertheless, thanks for spotting the error in Marc's Youtube link (he runs two channels). Now fixed in the article.

For easier reference, here is a copy of test footage (cropped in, scaled, graded) from Nikon Z6 FX ProRes RAW:

The article provides help to interpret what you see. In short, green/magenta is from debayering moiré, blue/yellow from pixel skipping.

I'll try hard to ignore Super8 from now on. Thanks.

Based on you Google Drive documents you did use the low res test pattern test that Jungbluth provided. 

My question in two earlier post was asking if this was normal and the test would be flawed by using a low res test chart.

I know for a fact rental houses and repair shops used approved professionally printed test charts for testing and repair.

You also post video test in all formats by recording the video monitor that's displaying the test chart.

 

You also crop in on the test chart without reference to any test video links. 

I ask for you to back up the integrity of your test.

 

[Super8]

Here's one of the test set-ups you used. 

My question is this normal to record test chart from a monitor screen?  I would think you have refresh rate and scan issues that would interfere  with the test.

My regards if I'm way off base and am asking to learn more about the process. - Thanks.

 

[Lars Steenhoff]

A monitor causes extra moire effects because of the pixel grid

[Falk Lumo]

2 hours ago, Super8 said:

My question is this normal to record test chart from a monitor screen?  I would think you have refresh rate and scan issues that would interfere  with the test.

My regards if I'm way off base and am asking to learn more about the process.

This looks like a sincere question to me. I withdraw my claim you‘re trolling and apologize.

I for myself have a professionally printed A2 version of my test chart. However, for a zone plate chart, even that shows signs of remaining printing artifacts. And Marc doesn‘t have any usable printed version.

However and because we only needed a small fraction of the test pattern, there is an established alternative in the testing scene: monitors! As odd as it may seem at first glance, they can be put to good use if a number of rules are respected. I know about at least one professional lens calibration company which is using monitors to display test charts. The most important rule is that monitor subpixels (their projection when photographed or filmed) must be MUCH smaller than a sensor pixel. Other rules are that the test pattern must be resolved with no aliasing, and that there is no flicker. We obeyed these rules. Which is also why we know to have no extra moiré effects from the pixel grid.

It is also the reason why:

1. the monitor shows a small fraction of the test chart only, such that the remaining part is fully resolved by the 3840px wide monitor. The original test chart is 8400px wide and 9.6MB large. It‘s pixels are displayed at 100% or 1:1. There is no moiré in the screen display to the naked eye. The test chart file was carefully created to avoid aliasing as much as possible, by myself. Which is no easy task for a zone plate chart.

2. the monitor appears so small in the video, as it is far away. This makes the monitor pixels and subpixels disappear completely, there are more than 10 monitor pixels per camera pixel ... Hard to beat with any printed chart! It also ensures that we have spatial frequencies beyond 4k to test for. This is crucial for the test and any attempt to reproduce our results!

3. minor sources of blur (lens, focus, motion) destroy results as we depend on high spatial frequencies being resolved.

Btw, the article DOES contain a link to a test video before cropping.

[Video Hummus]

HDMI 2.0 would have a sufficient data rate at 14.4 Gbps and supports up to 16bits (but not at 4K).

HDMI 2.1 can do up to 42.6 Gbps.

How Atomos is using that bandwidth I’m not sure...

[Super8]

5 minutes ago, Falk Lumo said:

This looks like a sincere question to me. I withdraw my claim you‘re trolling and apologize.

I for myself have a professionally printed A2 version of my test chart. However, for a zone plate chart, even that shows signs of remaining printing artifacts. And Marc doesn‘t have any usable printed version.

However and because we only needed a small fraction of the test pattern, there is an established alternative in the testing scene: monitors! As odd as it may seem at first glance, they can be put to good use if a number of rules are respected. I know about at least one professional lens calibration company which is using monitors to display test charts. The most important rule is that monitor subpixels (their projection when photographed or filmed) must be MUCH smaller than a sensor pixel. Other rules are that the test pattern must be resolved with no aliasing, and that there is no flicker. We obeyed these rules. Which is also why we know to have no extra moiré effects from the pixel grid.

It is also the reason why:

1. the monitor shows a small fraction of the test chart only, such that the remaining part is fully resolved by the 3840px wide monitor. The original test chart is 8400px wide and 9.6MB large. It‘s pixels are displayed at 100% or 1:1. There is no moiré in the screen display to the naked eye. The test chart file was carefully created to avoid aliasing as much as possible, by myself. Which is no easy task for a zone plate chart.

2. the monitor appears so small in the video, as it is far away. This makes the monitor pixels and subpixels disappear completely, there are about 10 monitor pixels per camera pixel ... Hard to beat with any printed chart! It also ensures that we have spatial frequencies beyond 4k to test for. This is crucial for the test and any attempt to reproduce our results!

Btw, the article DOES contain a link to a test video before cropping.

Thanks for the reply. 

Based on your filming the test chart on a monitor you were able to verify the 6k to 4k down sample internal recording that showed full sensor readout and no line skipping?

[Falk Lumo]

13 minutes ago, Super8 said:

Thanks for the reply. 

Based on your filming the test chart on a monitor you were able to verify the 6k to 4k down sample internal recording that showed full sensor readout and no line skipping?

Yes. For internal and external N-Log. But it‘s really all in the article ...

P.S. If you try to replicate results, I recommend to use an even larger distance or wider focal length. It would help to understand the math of zone plates (to estimate such things) - but you can use trial and error too.

[hmcindie]

41 minutes ago, gingercat said:

Shooting an aliasing test chart on a computer monitor is likely to create aliasing and moire - especially then showing a tightly cropped portion. A monitor can create all sorts of artefacts because of mismatched refresh rates with the camera. A test with a high quality printed chart is much more reliable. I've looked closely at a number of 4K RAW clips with very fine detail from the Z6 & Ninja V and could not see excessive aliasing.

If your not looking at a zone testplate you will probably not see that much aliasing even if the 4k lineskips like crazy. The Sony a7r line did that at least in the older models in 4k too and no one cares.

[Falk Lumo]

Hi, as I wrote in my blog article, field tests are missing and I am interested to learn about the practical impact myself.

OTOH, external 10 bit N-Log may be just as good and may have less risk of flickering (between frames) at lines, edges or fine regular structures like roof tiles or fashion texture. That would be the real-world test I am most interested in.

@gingercat

Quote

Shooting an aliasing test chart on a computer monitor is likely to create aliasing and moire

That's absolutely not the case here. The topic has been dealt with in replies above.

[Super8]

3 hours ago, Falk Lumo said:

Hi, as I wrote in my blog article, field tests are missing and I am interested to learn about the practical impact myself.

 

I disagree with you passing on information without thoroughly rigorous testing. 

- What model monitor do you have?

- Why can't you purchase a "test with a high quality printed chart"? or go to a facility that has one?

- When and where did you send your Z6 in for the Pro Res RAW service update?

The first thing you do when testing anything is to establish solid truths and benchmarks.

Why you didn't film that same monitor test pattern with a non line skipping, moire, artifact producing camera, so you had a benchmark to work from blows my mind.

Let's say your test is not accurate because you are filming with a monitor screen. Then what?  The damage has been done already.

 

[Eno]

This looks like line skipping and not pixel binning!

+ Other people are reporting higher noise levels typically associated with line skipping.

This is such a same and a lost opportunity for Nikon!

[Falk Lumo]

@Eno, you are right absolutely. My article says skipping, not binning.

Andrew posted in this thread and I replied already that it is pixel skipping, not binning. And that bit depth has nothing to do with it, as video readouts are all 12 bit. His post and my reply to him got removed, unfortunately.

[Eno]

@Falk Lumo

Some people confuse the terms but there is a fundamental between pixel binning and line skipping, the later being the worst possible way to read a sensor for video. Line skipping  exhibits huge more, aliasing effects and reduced low light performance (exactly like on the Z6 RAW output).

[Super8]

2 hours ago, Eno said:

This is such a same and a lost opportunity for Nikon!

I honestly question the motivation of Falk Lumo and your post.

This footage looks absolutely great.  Where are all the issues you describe? (Line skipping  exhibits huge more, aliasing effects and reduced low light performance) ????

I'm waiting on Andrews review of Nikon's Pro Res RAW.

Not a lost opportunity for Nikon.

 

[Super8]

1 hour ago, Falk Lumo said:

@Eno, you are right absolutely. My article says skipping, not binning.

Andrew posted in this thread and I replied already that it is pixel skipping, not binning. And that bit depth has nothing to do with it, as video readouts are all 12 bit. His post and my reply to him got removed, unfortunately.

Andrew's post and your reply back are still in this thread. 

[gethin]

I just watched that newsshooter vid and agree it looks great.  I was peeping for moire and I didn't see any.  

Need to see more footage before reaching any conclusions

[Falk Lumo]

14 hours ago, Falk Lumo said:

Andrew posted in this thread and I replied already that it is pixel skipping, not binning. And that bit depth has nothing to do with it, as video readouts are all 12 bit. His post and my reply to him got removed, unfortunately.

Erratum: it wasn‘t removed (as Super8 pointed out correctly), it is on the previous page.

 

[Falk Lumo]

1 hour ago, gingercat said:

I still contend that that using a test chart on a computer monitor is a not a reliable method to measure aliasing and moire.

I do understand the researvations against using a computer monitor to act as a test chart. Many things can go wrong then. But if done right, it is a superior method actually as it is far easier to control the effect of the printing pattern, or monitor pixel grid, resp. I've done both methods in the past and I can assure that - the way *we* did it - a professional test chart would render identical results. Everybody is free to professionally print the chart (Super A3 would be the minimal size required) and reproduce (or falsify) results - all required information is public and linked in the blog article.

[Super8]

3 hours ago, Falk Lumo said:

I do understand the researvations against using a computer monitor to act as a test chart. Many things can go wrong then. But if done right, it is a superior method actually as it is far easier to control the effect of the printing pattern, or monitor pixel grid, resp. I've done both methods in the past and I can assure that - the way *we* did it - a professional test chart would render identical results. Everybody is free to professionally print the chart (Super A3 would be the minimal size required) and reproduce (or falsify) results - all required information is public and linked in the blog article.

Cameo 40" Resolution Analysis Chart

https://www.abelcine.com/buy/lenses-accessories/optical-evaluation-tools/cameo-40-resolution-analysis-chart

I think this is the reason why you use the monitor instead of a professional test chart.  $1,200 for a test chart.

You might want to consider benchmark testing would also validate what you're doing.  Benchmark a cine camera that's in basic terms "gets it right". 

No other Nikon footage is displaying what you claim that sensor is doing. 

 

 

 

[nickname]

there´s a video up now on youtube that has a brick wall.

 

 

 

before this i also hadn´t seen any aliasing...