Jump to content


Photo

The war on resolutions..


  • Please log in to reply
5 replies to this topic

#1 Cesar Rubio

Cesar Rubio
  • Basic Members
  • PipPipPipPip
  • 263 posts
  • Digital Image Technician
  • Mexico/Wisconsin

Posted 07 November 2011 - 03:44 PM

Ok, given the recent hype about camera output resolutions and different companies approaching it differently, here is my take on the matter.

At first I am going to talk purely about output resolutions in cameras, and not compression, that is another important subject too, but to simplify things we are going to assume that all cameras record Uncompressed for the best IQ (Image Quality)


The first approach for resolution in professional cameras was, and still is in the broadcasting world, the use of 3 sensor cameras. This is TRUE resolution. Comparable to a film scan where you sample every RGB (Red-Green-Blue) color in every "pixel".


Then later on the single Bayer sensor showed up in the professional camera market. The sensor samples resolution and color in a different way, and "interpolates" or "guesses" the missing information while debayering the image. See here for more info about Bayer sensors:


http://en.wikipedia....ki/Bayer_filter


Out of this approach, newer Bayer sensor cameras like the Sony F65 and Canon C300 samples the Bayer sensor resolution 1/4", or every single color pixel to give a "true" final resolution output (no interpolation here).


So lets compare the 3 examples:


I would rate the 3 sensors cameras and the Bayer ¼ individual color sampling ratio as the same resolution.


That is, a 1080p 3 sensors camera will give you the same resolution as an Quad-HDp (3840x2160 pxs) sensor camera outputting a final 1080p (1920x 1080 pxs) resolution...like the Canon C300 for example.


A 1080p Bayer sensor camera would give you a true 1/4" resolution if its doing the interpolation on "the fly" or in real time...or a true 960x540 pxs final resolution.


BUT, the "magic" on the Bayer sensor works in a good (read=slow) quality debayering in post to give you a "higher" resolution. Using the best debayering settings, I get an "increase" of X1.5 times the final true resolution.

That's why I rate a 1080p Bayer sensor camera resolution as being as a "true" 720p one (1280x720 pxs) instead of the 540p (960x540 pxs) that really is.

So in order for a Single Bayer sensor camera to compete with 3 sensors or a Bayer ¼ sampling, we need 1.5 times more resolution that the intended final resolution.


The Alexa camera having a 2880x1620 pxs single Bayer sensor, and output that resolution in Raw mode, will give you a "clean" 1080p final resolution when you downsample the footage in post after debayering it.


In conclusion:

The Canon C300, and the Arri Alexa will give you about the same final resolution when used in the highest recording settings.


The Scarlet in 4K capture, will give you a 2.7K true resolution (2730x1440 pxs) so it wins in the final resolution output over the C300 and the Alexa.


But in the compression department, the Alexa wins when recording Arriraw (Uncompressed Raw), followed by the Scarlet and at the end is the Canon C300 camera.


Pick what is important for you, final resolution vs compression, and you can make an easy decision what camera system is the best suited for your needs and workflow.

Thanks,
Cesar Rubio.
Wisconsin & L.A.
http://dna-rubio-3d.blogspot.com/
http://dnarubio3d.wordpress.com/
  • 0

#2 Freya Black

Freya Black
  • Basic Members
  • PipPipPipPip
  • 4161 posts
  • Other
  • Went over the edge... Central Europe

Posted 07 November 2011 - 04:23 PM


Pick what is important for you, final resolution vs compression, and you can make an easy decision what camera system is the best suited for your needs and workflow.


I'm not sure I would be bothered about either so much as how beautiful the final images are. Resolution in paticular would probably be the least of my concerns. The most anybody is likely to see the work at will be 1080p but in practice DVD resolution might be more likely. It should be about how beautiful the images are, not about how high the numbers are.

love

Freya
  • 0

#3 John Sprung

John Sprung
  • Sustaining Members
  • 4635 posts
  • Other

Posted 07 November 2011 - 05:28 PM

The Canon C300, and the Arri Alexa will give you about the same final resolution when used in the highest recording settings.


I'd want to test that on Marconi charts and zone plates before reaching any conclusion. Canon does a really simple deBayer -- They average pairs of greens, and take the red and blue as-is. I'd look for color fringes on sharp diagonals. Also important to test how the 8 bit depth limits color timing.




-- J.S.
  • 0

#4 Cesar Rubio

Cesar Rubio
  • Basic Members
  • PipPipPipPip
  • 263 posts
  • Digital Image Technician
  • Mexico/Wisconsin

Posted 07 November 2011 - 07:37 PM

I'm not sure I would be bothered about either so much as how beautiful the final images are. Resolution in paticular would probably be the least of my concerns. The most anybody is likely to see the work at will be 1080p but in practice DVD resolution might be more likely. It should be about how beautiful the images are, not about how high the numbers are.

love

Freya


Agreed Freya.

For regular Cinema screens(35 feet wide) we need at least true 1080p/2K resolution. (IMAX is another different beast...)

That's why for me, I will settle for that resolution and start looking for other important things in a camera to make a beautiful image, like higher dynamic range, higher base ISO/ASA at 0db with little or no noise and uncompressed Capture

And yes, most people still watch at home everything in DVD...SD def!

In most video stores, the Blu-ray selections is very little in comparison to DVD's....so for the time being standard definition is not going anywhere anytime soon!

Anyways, most people don't care much about resolution, but good content in movies they watch. Story is still king!

Cesar Rubio.
Wisconsin & L.A.
http://dna-rubio-3d.blogspot.com/
http://dnarubio3d.wordpress.com/


  • 0

#5 Cesar Rubio

Cesar Rubio
  • Basic Members
  • PipPipPipPip
  • 263 posts
  • Digital Image Technician
  • Mexico/Wisconsin

Posted 07 November 2011 - 07:42 PM

I'd want to test that on Marconi charts and zone plates before reaching any conclusion. Canon does a really simple deBayer -- They average pairs of greens, and take the red and blue as-is. I'd look for color fringes on sharp diagonals. Also important to test how the 8 bit depth limits color timing.


-- J.S.


You are right John.

Probably we should leave such detailed comparison tests to Geoff Boyle or Phil Bloom...

But in all my experience watching and playing with video content, I can almost warranty you that my conclusions are pretty close to the real deal...

Mathematics and physics never lie..

Thanks,

Cesar Rubio.
Wisconsin & L.A.
http://dna-rubio-3d.blogspot.com/

http://dnarubio3d.wordpress.com/

  • 0

#6 Cesar Rubio

Cesar Rubio
  • Basic Members
  • PipPipPipPip
  • 263 posts
  • Digital Image Technician
  • Mexico/Wisconsin

Posted 07 November 2011 - 09:49 PM

And you know what else....

Since this thread is focused on 3-D, there is more to add about regarding resolution.

3-D as is projecting double images at the same time, increases resolution at about 1.5 times.

And higher frame rates, like 48fps or even 60fps increases the perceived resolution even further....

So we are just "fine" with 2K resolution for regular 3-D Cinema...for still a good time to come.

The most powerful single 3-D projectors out there can only handle 2k at 60 fps max....and NOT all Cinemas have them yet as they are very expensive!

Cesar Rubio.
Wisconsin & L.A.
http://dna-rubio-3d.blogspot.com/
http://dnarubio3d.wordpress.com/


  • 0


Glidecam

Media Blackout - Custom Cables and AKS

CineLab

CineTape

The Slider

Ritter Battery

Broadcast Solutions Inc

Visual Products

Abel Cine

Metropolis Post

Rig Wheels Passport

Aerial Filmworks

Paralinx LLC

Opal

Technodolly

Gamma Ray Digital Inc

Tai Audio

rebotnix Technologies

FJS International, LLC

Willys Widgets

Wooden Camera

Opal

Glidecam

CineLab

Aerial Filmworks

rebotnix Technologies

Media Blackout - Custom Cables and AKS

The Slider

Tai Audio

Willys Widgets

Wooden Camera

Gamma Ray Digital Inc

Broadcast Solutions Inc

Technodolly

FJS International, LLC

Rig Wheels Passport

Visual Products

Paralinx LLC

Ritter Battery

CineTape

Metropolis Post

Abel Cine