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BMD 12K test results now available


Geoff Boyle
 

Having waited to publish until a production camera was available...

 

The results of the tests at the NFA this week are now available https://cinematography.net/BMD-12K.html

 

The BRAW files are also linked from this page, a 32mm Cooke Mini S4 was used.

 

My purely personal reaction is that I can grade back a useful picture from -3 to +4.5 stops, albeit with some noise reduction on the underexposed shots. I’m impressed by the highlights where you can clearly see the 1/3rd of a stop darker square within the white on the stress test chart at +4.5 stops.

Something strange is happening with extreme overexposure of fine detail...

 

cheers
Geoff Boyle NSC FBKS
EU based cinematographer
+31 637155076

www.gboyle.nl

www.cinematography.net

Become a CML Patron https://www.patreon.com/bePatron?u=43292735

 

 


Colin Elves
 

One would assume that the monochromatic pixels hit saturation before the coloured sensels do so it might not be too surprising that the camera appears to lose resolution once they have, no?

Colin Elves
Director of Photography
Brussels



On 10 Oct 2020, at 07:42, Geoff Boyle <geoff@...> wrote:

Something strange is happening with extreme overexposure of fine detail...

 

cheers
Geoff Boyle NSC FBKS
EU based cinematographer
+31 637155076

www.gboyle.nl

www.cinematography.net

Become a CML Patron https://www.patreon.com/bePatron?u=43292735


Geoff Boyle
 

It’s not losing resolution there appears to be an increase in chroma aliasing.

 

cheers
Geoff Boyle NSC FBKS
EU based cinematographer
+31 637155076

www.gboyle.nl

www.cinematography.net

Become a CML Patron https://www.patreon.com/bePatron?u=43292735

 

 

From: cml-raw-log-hdr@... <cml-raw-log-hdr@...> On Behalf Of Colin Elves
Sent: Saturday, 10 October 2020 08:03
To: cml-raw-log-hdr@...
Subject: Re: [cml-raw-log-hdr] BMD 12K test results now available

 

One would assume that the monochromatic pixels hit saturation before the coloured sensels do so it might not be too surprising that the camera appears to lose resolution once they have, no?

Colin Elves

Director of Photography

Brussels

 

 



On 10 Oct 2020, at 07:42, Geoff Boyle <geoff@...> wrote:

 

Something strange is happening with extreme overexposure of fine detail...

 

cheers
Geoff Boyle NSC FBKS
EU based cinematographer
+31 637155076

www.gboyle.nl

www.cinematography.net

Become a CML Patron https://www.patreon.com/bePatron?u=43292735


Colin Elves
 

Surely that’s due to a loss in resolution? Even if after processing it appears to be a loss of colour resolution. 

It certainly looks like the sort of aliasing you get with cameras that ‘pixel group’ to reduce resolution without windowing the sensor.

But maybe this can be addressed through an improvement in the debayer algorithm. 

Colin Elves
Director of Photography
Brussels


On 10 Oct 2020, at 08:21, Geoff Boyle <geoff@...> wrote:



It’s not losing resolution there appears to be an increase in chroma aliasing.

 

cheers
Geoff Boyle NSC FBKS
EU based cinematographer
+31 637155076

www.gboyle.nl

www.cinematography.net

Become a CML Patron https://www.patreon.com/bePatron?u=43292735

 

 


alister@...
 

It certainly has some interesting characteristics. There is a lot of noise in the red channel.

I’m with Colin in so much as if the white pixels are totally saturated then they can no longer discern bright textures so they may as well not be there in terms of resolving those brighter textures.  The resolution in the Braw Luma bitmap will be dropping to zero and this is possibly exacerbated by the way the debayer process will still be trying to use the various RGB pixel outputs to fill in the gaps. The coloured aliasing might be something that can be reduced with fine tuning of the delayer algorithm, but right now highlights are not pretty.


Alister Chapman 

Cinematographer - DIT - Consultant
UK Mobile/Whatsapp +44 7711 152226


Facebook: Alister Chapman
Twitter: @stormguy



www.xdcam-user.com    1.5 million hits, 100,000 visits from over 45,000 unique visitors every month!  Film and Video production techniques, reviews and news.


















On 10 Oct 2020, at 07:30, Colin Elves <colin@...> wrote:

Surely that’s due to a loss in resolution? Even if after processing it appears to be a loss of colour resolution. 

It certainly looks like the sort of aliasing you get with cameras that ‘pixel group’ to reduce resolution without windowing the sensor.

But maybe this can be addressed through an improvement in the debayer algorithm. 

Colin Elves
Director of Photography
Brussels


On 10 Oct 2020, at 08:21, Geoff Boyle <geoff@...> wrote:


It’s not losing resolution there appears to be an increase in chroma aliasing.
 
cheers 
Geoff Boyle NSC FBKS
EU based cinematographer
+31 637155076
 
 


Geoff Boyle
 

I have to say that in all the normal footage, ie scenics, that I've shot this has never shown up.
I also like the colour response of the camera.

On Sat, 10 Oct 2020, 11:10 , <alister@...> wrote:
It certainly has some interesting characteristics. There is a lot of noise in the red channel.

I’m with Colin in so much as if the white pixels are totally saturated then they can no longer discern bright textures so they may as well not be there in terms of resolving those brighter textures.  The resolution in the Braw Luma bitmap will be dropping to zero and this is possibly exacerbated by the way the debayer process will still be trying to use the various RGB pixel outputs to fill in the gaps. The coloured aliasing might be something that can be reduced with fine tuning of the delayer algorithm, but right now highlights are not pretty.


Alister Chapman 

Cinematographer - DIT - Consultant
UK Mobile/Whatsapp +44 7711 152226


Facebook: Alister Chapman
Twitter: @stormguy



www.xdcam-user.com    1.5 million hits, 100,000 visits from over 45,000 unique visitors every month!  Film and Video production techniques, reviews and news.


















On 10 Oct 2020, at 07:30, Colin Elves <colin@...> wrote:

Surely that’s due to a loss in resolution? Even if after processing it appears to be a loss of colour resolution. 

It certainly looks like the sort of aliasing you get with cameras that ‘pixel group’ to reduce resolution without windowing the sensor.

But maybe this can be addressed through an improvement in the debayer algorithm. 

Colin Elves
Director of Photography
Brussels


On 10 Oct 2020, at 08:21, Geoff Boyle <geoff@...> wrote:


It’s not losing resolution there appears to be an increase in chroma aliasing.
 
cheers 
Geoff Boyle NSC FBKS
EU based cinematographer
+31 637155076
 
 


Pawel Achtel ACS
 

Ø  It’s not losing resolution there appears to be an increase in chroma aliasing.

 

Hey Geoff,

 

          Thank you for doing those tests for us. I know how much time and effort they take!

 

I’m looking at your “middle” exposure shot. I’m assuming that the chart was in focus and the lens was sharp because of severe Moiré issues:

 

 

Below is MTF chart and edge profile from your shot. The MTF 50 (the number of lines at which the contrast is at least 50%) of BMD “12K” is around 1207 LW/PH, which is significantly lower than, for example, ARRI ALEXA LF (1989 Line Widths/ Picture Height) or RED Monstro (1736 LW/PH) and about one quarter of the sharpness of the 9x7, which scored well over 4,000 LW/PH with contrast above 50%.

 

The resolving limit is also less than half of Nyquist spatial frequency (less than most 4K Bayer CFA cameras would normally deliver and more in line with a 2K ~ 3K camera):

 

 

Indeed, this can be compared with MTF of ARRI Alexa LF below which, despite significantly lower pixel count, delivers significantly higher sharpness as well as higher resolving limit. And, it does so without any artefacts (that I can see). I have not observed any aliasing or Moiré.

 

 

And, here is the MTF for RED Monstro 8K, which is still heaps sharper than BMD “12K” (and is probably even sharper with genuine OLPF, which I still haven’t had a chance to test):

 

 

The colour fringing problem in Ursa “12K” can be clrearly seen in the edge profile below. This isn’t CA of the lens. It is colour artefacting due to insufficient blurring in relation to colour sampling.

 

 

As I mentioned earlier, this type of RGBW CFA requires much higher level of high spatial frequency filtering (blurring) and significantly increased CoC compared to Bayer CFA. I guess it also helps with high compression ratios, but the detail is gone. The small detail is all 0% contrast and no amount of sharpening can bring it back. And, if you can bring it back, it is all colour artefacts and fringing. I think it is incorrect to call it a “12K” camera in the same manner as Bayer CFA Sensor cameras are referred to. It is really a 3K or, at best (and this is stretching it), a 4K equivalent of Bayer CFA camera in the actual images that it can produce.

 

When this blurring (down to about 3K equivalent of Bayer sensor camera) is done, indeed the colour and dynamic range have a potential to be better than that of a Bayer sensor camera.  

 

However, another unusual thing that I noticed is that there is a lot of noise and “muddiness” in dark grey patches - much more so than in black patches and much more than I have seen in most other digital cinema cameras:

 

 

 

 

          This can be a more tricky to deal with. Noise in black areas can be somewhat mitigated by raising the black level, but this doesn’t work with dark grey areas.

 

 

Kind Regards,

 

Pawel Achtel ACS B.Eng.(Hons) M.Sc.

“Sharp to the Edge”

 

ACHTEL PTY LIMITED, ABN 52 134 895 417

Website: www.achtel.com

Mobile: 040 747 2747 (overseas: +61 4 0747 2747)

Mail: PO BOX 557, Rockdale, NSW 2216, Australia

Address: RA 913 Coles Bay Rd., Coles Bay, TAS 7215, Australia

Location: S 42° 0'14.40"S, E 148°14'47.13"

Email: Pawel.Achtel@...

Facebook: facebook.com/PawelAchtel

Twitter: twitter.com/PawelAchtel

Skype: Pawel.Achtel

 


Geoff Boyle
 

Hi Pawel,

 

Not sure what you’re using to read the files bu in the latest version of Resolve the attached is what I get with a 10X zoom.

Starting at 11.5K, shot with a Cooke 32mm Mini S4 and it looks sharp at normal zoom.

 

cheers
Geoff Boyle NSC FBKS
EU based cinematographer
+31 637155076

www.gboyle.nl

www.cinematography.net

Become a CML Patron https://www.patreon.com/bePatron?u=43292735

 

 

From: cml-raw-log-hdr@... <cml-raw-log-hdr@...> On Behalf Of Pawel Achtel ACS
Sent: Sunday, 11 October 2020 07:56
To: cml-raw-log-hdr@...
Subject: Re: [cml-raw-log-hdr] BMD 12K test results now available

 

  • It’s not losing resolution there appears to be an increase in chroma aliasing.

 

Hey Geoff,

 

          Thank you for doing those tests for us. I know how much time and effort they take!

 

I’m looking at your “middle” exposure shot. I’m assuming that the chart was in focus and the lens was sharp because of severe Moiré issues:

 

 

Below is MTF chart and edge profile from your shot. The MTF 50 (the number of lines at which the contrast is at least 50%) of BMD “12K” is around 1207 LW/PH, which is significantly lower than, for example, ARRI ALEXA LF (1989 Line Widths/ Picture Height) or RED Monstro (1736 LW/PH) and about one quarter of the sharpness of the 9x7, which scored well over 4,000 LW/PH with contrast above 50%.

 

The resolving limit is also less than half of Nyquist spatial frequency (less than most 4K Bayer CFA cameras would normally deliver and more in line with a 2K ~ 3K camera):

 

 

Indeed, this can be compared with MTF of ARRI Alexa LF below which, despite significantly lower pixel count, delivers significantly higher sharpness as well as higher resolving limit. And, it does so without any artefacts (that I can see). I have not observed any aliasing or Moiré.

 

 

And, here is the MTF for RED Monstro 8K, which is still heaps sharper than BMD “12K” (and is probably even sharper with genuine OLPF, which I still haven’t had a chance to test):

 

 

The colour fringing problem in Ursa “12K” can be clrearly seen in the edge profile below. This isn’t CA of the lens. It is colour artefacting due to insufficient blurring in relation to colour sampling.

 

 

As I mentioned earlier, this type of RGBW CFA requires much higher level of high spatial frequency filtering (blurring) and significantly increased CoC compared to Bayer CFA. I guess it also helps with high compression ratios, but the detail is gone. The small detail is all 0% contrast and no amount of sharpening can bring it back. And, if you can bring it back, it is all colour artefacts and fringing. I think it is incorrect to call it a “12K” camera in the same manner as Bayer CFA Sensor cameras are referred to. It is really a 3K or, at best (and this is stretching it), a 4K equivalent of Bayer CFA camera in the actual images that it can produce.

 

When this blurring (down to about 3K equivalent of Bayer sensor camera) is done, indeed the colour and dynamic range have a potential to be better than that of a Bayer sensor camera.  

 

However, another unusual thing that I noticed is that there is a lot of noise and “muddiness” in dark grey patches - much more so than in black patches and much more than I have seen in most other digital cinema cameras:

 

 

 

 

          This can be a more tricky to deal with. Noise in black areas can be somewhat mitigated by raising the black level, but this doesn’t work with dark grey areas.

 

 

Kind Regards,

 

Pawel Achtel ACS B.Eng.(Hons) M.Sc.

“Sharp to the Edge”

 

ACHTEL PTY LIMITED, ABN 52 134 895 417

Website: www.achtel.com

Mobile: 040 747 2747 (overseas: +61 4 0747 2747)

Mail: PO BOX 557, Rockdale, NSW 2216, Australia

Address: RA 913 Coles Bay Rd., Coles Bay, TAS 7215, Australia

Location: S 42° 0'14.40"S, E 148°14'47.13"

Email: Pawel.Achtel@...

Facebook: facebook.com/PawelAchtel

Twitter: twitter.com/PawelAchtel

Skype: Pawel.Achtel

 


Geoff Boyle
 

Interesting, the first frame I posted was with Filter one at T22, this one is with filter 4, 6 stops ND, at T2.8...

 

So, the Cooke is much sharper wide open 😊

 

cheers
Geoff Boyle NSC FBKS
EU based cinematographer
+31 637155076

www.gboyle.nl

www.cinematography.net

Become a CML Patron https://www.patreon.com/bePatron?u=43292735

 

 

From: cml-raw-log-hdr@... <cml-raw-log-hdr@...> On Behalf Of Geoff Boyle
Sent: Sunday, 11 October 2020 08:29
To: cml-raw-log-hdr@...
Subject: Re: [cml-raw-log-hdr] BMD 12K test results now available

 

Hi Pawel,

 

Not sure what you’re using to read the files bu in the latest version of Resolve the attached is what I get with a 10X zoom.

Starting at 11.5K, shot with a Cooke 32mm Mini S4 and it looks sharp at normal zoom.

 

cheers
Geoff Boyle NSC FBKS
EU based cinematographer
+31 637155076

www.gboyle.nl

www.cinematography.net

Become a CML Patron https://www.patreon.com/bePatron?u=43292735

 

 

From: cml-raw-log-hdr@... <cml-raw-log-hdr@...> On Behalf Of Pawel Achtel ACS
Sent: Sunday, 11 October 2020 07:56
To: cml-raw-log-hdr@...
Subject: Re: [cml-raw-log-hdr] BMD 12K test results now available

 

  • It’s not losing resolution there appears to be an increase in chroma aliasing.

 

Hey Geoff,

 

          Thank you for doing those tests for us. I know how much time and effort they take!

 

I’m looking at your “middle” exposure shot. I’m assuming that the chart was in focus and the lens was sharp because of severe Moiré issues:

 

 

Below is MTF chart and edge profile from your shot. The MTF 50 (the number of lines at which the contrast is at least 50%) of BMD “12K” is around 1207 LW/PH, which is significantly lower than, for example, ARRI ALEXA LF (1989 Line Widths/ Picture Height) or RED Monstro (1736 LW/PH) and about one quarter of the sharpness of the 9x7, which scored well over 4,000 LW/PH with contrast above 50%.

 

The resolving limit is also less than half of Nyquist spatial frequency (less than most 4K Bayer CFA cameras would normally deliver and more in line with a 2K ~ 3K camera):

 

 

Indeed, this can be compared with MTF of ARRI Alexa LF below which, despite significantly lower pixel count, delivers significantly higher sharpness as well as higher resolving limit. And, it does so without any artefacts (that I can see). I have not observed any aliasing or Moiré.

 

 

And, here is the MTF for RED Monstro 8K, which is still heaps sharper than BMD “12K” (and is probably even sharper with genuine OLPF, which I still haven’t had a chance to test):

 

 

The colour fringing problem in Ursa “12K” can be clrearly seen in the edge profile below. This isn’t CA of the lens. It is colour artefacting due to insufficient blurring in relation to colour sampling.

 

 

As I mentioned earlier, this type of RGBW CFA requires much higher level of high spatial frequency filtering (blurring) and significantly increased CoC compared to Bayer CFA. I guess it also helps with high compression ratios, but the detail is gone. The small detail is all 0% contrast and no amount of sharpening can bring it back. And, if you can bring it back, it is all colour artefacts and fringing. I think it is incorrect to call it a “12K” camera in the same manner as Bayer CFA Sensor cameras are referred to. It is really a 3K or, at best (and this is stretching it), a 4K equivalent of Bayer CFA camera in the actual images that it can produce.

 

When this blurring (down to about 3K equivalent of Bayer sensor camera) is done, indeed the colour and dynamic range have a potential to be better than that of a Bayer sensor camera.  

 

However, another unusual thing that I noticed is that there is a lot of noise and “muddiness” in dark grey patches - much more so than in black patches and much more than I have seen in most other digital cinema cameras:

 

 

 

 

          This can be a more tricky to deal with. Noise in black areas can be somewhat mitigated by raising the black level, but this doesn’t work with dark grey areas.

 

 

Kind Regards,

 

Pawel Achtel ACS B.Eng.(Hons) M.Sc.

“Sharp to the Edge”

 

ACHTEL PTY LIMITED, ABN 52 134 895 417

Website: www.achtel.com

Mobile: 040 747 2747 (overseas: +61 4 0747 2747)

Mail: PO BOX 557, Rockdale, NSW 2216, Australia

Address: RA 913 Coles Bay Rd., Coles Bay, TAS 7215, Australia

Location: S 42° 0'14.40"S, E 148°14'47.13"

Email: Pawel.Achtel@...

Facebook: facebook.com/PawelAchtel

Twitter: twitter.com/PawelAchtel

Skype: Pawel.Achtel

 


Geoff Boyle
 

Definitely Chroma aliasing as the attached shots show. They are 2, 3 & 4 stops overexposed and 10X zoom in to the centre of the image.

 

cheers
Geoff Boyle NSC FBKS
EU based cinematographer
+31 637155076

www.gboyle.nl

www.cinematography.net

Become a CML Patron https://www.patreon.com/bePatron?u=43292735

 

 

From: cml-raw-log-hdr@... <cml-raw-log-hdr@...> On Behalf Of Geoff Boyle
Sent: Sunday, 11 October 2020 09:00
To: cml-raw-log-hdr@...
Subject: Re: [cml-raw-log-hdr] BMD 12K test results now available

 

Interesting, the first frame I posted was with Filter one at T22, this one is with filter 4, 6 stops ND, at T2.8...

 

So, the Cooke is much sharper wide open 😊

 

cheers
Geoff Boyle NSC FBKS
EU based cinematographer
+31 637155076

www.gboyle.nl

www.cinematography.net

Become a CML Patron https://www.patreon.com/bePatron?u=43292735

 

 

From: cml-raw-log-hdr@... <cml-raw-log-hdr@...> On Behalf Of Geoff Boyle
Sent: Sunday, 11 October 2020 08:29
To: cml-raw-log-hdr@...
Subject: Re: [cml-raw-log-hdr] BMD 12K test results now available

 

Hi Pawel,

 

Not sure what you’re using to read the files bu in the latest version of Resolve the attached is what I get with a 10X zoom.

Starting at 11.5K, shot with a Cooke 32mm Mini S4 and it looks sharp at normal zoom.

 

cheers
Geoff Boyle NSC FBKS
EU based cinematographer
+31 637155076

www.gboyle.nl

www.cinematography.net

Become a CML Patron https://www.patreon.com/bePatron?u=43292735

 

 

From: cml-raw-log-hdr@... <cml-raw-log-hdr@...> On Behalf Of Pawel Achtel ACS
Sent: Sunday, 11 October 2020 07:56
To: cml-raw-log-hdr@...
Subject: Re: [cml-raw-log-hdr] BMD 12K test results now available

 

  • It’s not losing resolution there appears to be an increase in chroma aliasing.

 

Hey Geoff,

 

          Thank you for doing those tests for us. I know how much time and effort they take!

 

I’m looking at your “middle” exposure shot. I’m assuming that the chart was in focus and the lens was sharp because of severe Moiré issues:

 

 

Below is MTF chart and edge profile from your shot. The MTF 50 (the number of lines at which the contrast is at least 50%) of BMD “12K” is around 1207 LW/PH, which is significantly lower than, for example, ARRI ALEXA LF (1989 Line Widths/ Picture Height) or RED Monstro (1736 LW/PH) and about one quarter of the sharpness of the 9x7, which scored well over 4,000 LW/PH with contrast above 50%.

 

The resolving limit is also less than half of Nyquist spatial frequency (less than most 4K Bayer CFA cameras would normally deliver and more in line with a 2K ~ 3K camera):

 

 

Indeed, this can be compared with MTF of ARRI Alexa LF below which, despite significantly lower pixel count, delivers significantly higher sharpness as well as higher resolving limit. And, it does so without any artefacts (that I can see). I have not observed any aliasing or Moiré.

 

 

And, here is the MTF for RED Monstro 8K, which is still heaps sharper than BMD “12K” (and is probably even sharper with genuine OLPF, which I still haven’t had a chance to test):

 

 

The colour fringing problem in Ursa “12K” can be clrearly seen in the edge profile below. This isn’t CA of the lens. It is colour artefacting due to insufficient blurring in relation to colour sampling.

 

 

As I mentioned earlier, this type of RGBW CFA requires much higher level of high spatial frequency filtering (blurring) and significantly increased CoC compared to Bayer CFA. I guess it also helps with high compression ratios, but the detail is gone. The small detail is all 0% contrast and no amount of sharpening can bring it back. And, if you can bring it back, it is all colour artefacts and fringing. I think it is incorrect to call it a “12K” camera in the same manner as Bayer CFA Sensor cameras are referred to. It is really a 3K or, at best (and this is stretching it), a 4K equivalent of Bayer CFA camera in the actual images that it can produce.

 

When this blurring (down to about 3K equivalent of Bayer sensor camera) is done, indeed the colour and dynamic range have a potential to be better than that of a Bayer sensor camera.  

 

However, another unusual thing that I noticed is that there is a lot of noise and “muddiness” in dark grey patches - much more so than in black patches and much more than I have seen in most other digital cinema cameras:

 

 

 

 

          This can be a more tricky to deal with. Noise in black areas can be somewhat mitigated by raising the black level, but this doesn’t work with dark grey areas.

 

 

Kind Regards,

 

Pawel Achtel ACS B.Eng.(Hons) M.Sc.

“Sharp to the Edge”

 

ACHTEL PTY LIMITED, ABN 52 134 895 417

Website: www.achtel.com

Mobile: 040 747 2747 (overseas: +61 4 0747 2747)

Mail: PO BOX 557, Rockdale, NSW 2216, Australia

Address: RA 913 Coles Bay Rd., Coles Bay, TAS 7215, Australia

Location: S 42° 0'14.40"S, E 148°14'47.13"

Email: Pawel.Achtel@...

Facebook: facebook.com/PawelAchtel

Twitter: twitter.com/PawelAchtel

Skype: Pawel.Achtel

 


Pawel Achtel ACS
 

Ø  Filter one at T22, this one is with filter 4, 6 stops ND, at T2.8...

Ø  So, the Cooke is much sharper wide open 😊

At T22 it is diffraction limited (Airy disc size is about 34 mm) and equivalent to smearing 5mm layer of Vaseline on the lens, at T2.8 it is not 😊

 

Ø  Not sure what you’re using to read the files bu in the latest version of Resolve the attached is what I get with a 10X zoom.

Using Davinci Resolve 16.3b3 on Windows, which was released yesterday: straight on the 12K timeline, all defaults and Colour Science Gen 5.0, export to TIFF 16. Here is the output TIFF 16 frame:

 

https://drive.google.com/drive/folders/1BzJvfS8B0vi-6FZNgJHv33wAHcryMzgY?usp=sharing

 

Another thing is that Resolve 16.3b3 crashes almost 100% of the time with GPU out of memory error (I use GTX P6000). I’m not sure what the minimum GPU requirements are, but one would think 24GB would be enough for a single clip with no filter nodes.

 

Kind Regards,

 

Pawel Achtel ACS B.Eng.(Hons) M.Sc.

“Sharp to the Edge”

 

ACHTEL PTY LIMITED, ABN 52 134 895 417

Website: www.achtel.com

Mobile: 040 747 2747 (overseas: +61 4 0747 2747)

Mail: PO BOX 557, Rockdale, NSW 2216, Australia

Address: RA 913 Coles Bay Rd., Coles Bay, TAS 7215, Australia

Location: S 42° 0'14.40"S, E 148°14'47.13"

Email: Pawel.Achtel@...

Facebook: facebook.com/PawelAchtel

Twitter: twitter.com/PawelAchtel

Skype: Pawel.Achtel

 

From: cml-raw-log-hdr@... [mailto:cml-raw-log-hdr@...] On Behalf Of Geoff Boyle
Sent: Sunday, 11 October 2020 5:29 PM
To: cml-raw-log-hdr@...
Subject: Re: [cml-raw-log-hdr] BMD 12K test results now available

 

Hi Pawel,

 

Not sure what you’re using to read the files bu in the latest version of Resolve the attached is what I get with a 10X zoom.

Starting at 11.5K, shot with a Cooke 32mm Mini S4 and it looks sharp at normal zoom.

 

cheers
Geoff Boyle NSC FBKS
EU based cinematographer
+31 637155076

www.gboyle.nl

www.cinematography.net

Become a CML Patron https://www.patreon.com/bePatron?u=43292735

 

 

From: cml-raw-log-hdr@... <cml-raw-log-hdr@...> On Behalf Of Pawel Achtel ACS
Sent: Sunday, 11 October 2020 07:56
To: cml-raw-log-hdr@...
Subject: Re: [cml-raw-log-hdr] BMD 12K test results now available

 

Ø  It’s not losing resolution there appears to be an increase in chroma aliasing.

 

Hey Geoff,

 

          Thank you for doing those tests for us. I know how much time and effort they take!

 

I’m looking at your “middle” exposure shot. I’m assuming that the chart was in focus and the lens was sharp because of severe Moiré issues:

 

 

Below is MTF chart and edge profile from your shot. The MTF 50 (the number of lines at which the contrast is at least 50%) of BMD “12K” is around 1207 LW/PH, which is significantly lower than, for example, ARRI ALEXA LF (1989 Line Widths/ Picture Height) or RED Monstro (1736 LW/PH) and about one quarter of the sharpness of the 9x7, which scored well over 4,000 LW/PH with contrast above 50%.

 

The resolving limit is also less than half of Nyquist spatial frequency (less than most 4K Bayer CFA cameras would normally deliver and more in line with a 2K ~ 3K camera):

 

 

Indeed, this can be compared with MTF of ARRI Alexa LF below which, despite significantly lower pixel count, delivers significantly higher sharpness as well as higher resolving limit. And, it does so without any artefacts (that I can see). I have not observed any aliasing or Moiré.

 

 

And, here is the MTF for RED Monstro 8K, which is still heaps sharper than BMD “12K” (and is probably even sharper with genuine OLPF, which I still haven’t had a chance to test):

 

 

The colour fringing problem in Ursa “12K” can be clrearly seen in the edge profile below. This isn’t CA of the lens. It is colour artefacting due to insufficient blurring in relation to colour sampling.

 

 

As I mentioned earlier, this type of RGBW CFA requires much higher level of high spatial frequency filtering (blurring) and significantly increased CoC compared to Bayer CFA. I guess it also helps with high compression ratios, but the detail is gone. The small detail is all 0% contrast and no amount of sharpening can bring it back. And, if you can bring it back, it is all colour artefacts and fringing. I think it is incorrect to call it a “12K” camera in the same manner as Bayer CFA Sensor cameras are referred to. It is really a 3K or, at best (and this is stretching it), a 4K equivalent of Bayer CFA camera in the actual images that it can produce.

 

When this blurring (down to about 3K equivalent of Bayer sensor camera) is done, indeed the colour and dynamic range have a potential to be better than that of a Bayer sensor camera.  

 

However, another unusual thing that I noticed is that there is a lot of noise and “muddiness” in dark grey patches - much more so than in black patches and much more than I have seen in most other digital cinema cameras:

 

 

 

 

          This can be a more tricky to deal with. Noise in black areas can be somewhat mitigated by raising the black level, but this doesn’t work with dark grey areas.

 

 

Kind Regards,

 

Pawel Achtel ACS B.Eng.(Hons) M.Sc.

“Sharp to the Edge”

 

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Geoff Boyle
 

Final comment from me for the moment.

I’ve just looked through all the exposures at all the apertures zoomed in 10X.

The Cooke 32mm Mini S4 is great at T2.8 to T8, softens a little at T11, softens more at T16 and is very soft at T22.

I’ll have to include this test in all future camera and lens tests, this si the first time I’ve had this chart in the centre of frame like this. It is there to show issues like the colour aliasing but I hadn’t though of it as a lens test 😊

 

cheers
Geoff Boyle NSC FBKS
EU based cinematographer
+31 637155076

www.gboyle.nl

www.cinematography.net

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Mitch Gross
 

On Oct 11, 2020, at 3:26 AM, Geoff Boyle <geoff@...> wrote:

The Cooke 32mm Mini S4 is great at T2.8 to T8, softens a little at T11, softens more at T16 and is very soft at T22.



I think you’ll find this true of most S-35 lenses.


Mitch Gross
New York