CML - Cinematography Mailing List

Scanning At 2K 

Published : 26th September 2003

Hello :

 

When someone says scanned at 2K, what does that mean? Is it 2K vertical lines, or 2K horizontal pixels. If it is 2K vertical, then what is the horizontal pixel count, and if it is 2K horizontal then what is the Vertical lines.

 

Compared to HD (I know different list), Is HD 1920 Vertical or Horizontal? Which part is the 1080?

 

Thanks, I think I know, I just want to be certain.

 

Steven Gladstone

Cinematographer - Gladstone Films

style="margin-top:0;">East Coast List administrator - CML


Steven Gladstone wrote :

 

>When someone says scanned at 2K, what does that mean? Is it 2K >vertical lines, or 2K horizontal pixels.

 

Cineon systems use the following sizes (pixels across the 35mm frame x lines per picture):

 

4096 x 3112 -> '4K' Full app

2096 x 1556 -> '2K' Full app

 

Scope uses :

 

3656 x 3112 -> '4K' scope

1828 x 1556 -> '2K' scope

 

Academy uses :

 

3656 x 2664 -> '4K' Academy

1828 x 1332 -> '2K' Academy

 

In the Lightning scanner case these are cropped from the 4K line array with the same area of film always being imaged onto the sensor. The 2K outputs are downsampled from the 4K on the fly.

 

In each case the 'K' is a base 2 number as opposed to a base 10 :

 

1K -> 2^10 -> 1024

2K -> 2^11 -> 2048

4K -> 2^12 -> 4096

 

When doing vista the frames are on their side so you get :

 

6114 x 4096 -> '4K' vista

3112 x 2048 -> '2K' vista

 

i.e. 2x the size of the full app version -> 4096 x (3112*2) = 4096 x 6114 turned on its side becomes 6114 x 4096.

 

In each case the size is based upon the number of pixels used to sample the width of the 35mm.

 

class="style9" >Compared to HD (I know different list), Is HD 1920 Vertical or >Horizontal?

class="style9" >Which part is the 1080?

 

Excluding interlaced formats HD gives you :

 

1920 x 1080 (1080p versions)

 

style="margin-top:0;">1280 x 720 (720p versions)

so 1080 is the number of lines.

 

Note : These numbers have only a passing relationship to resolution in that they dictate the theoretical maximum MTF but lots of things lower this in practice, so its a bit apples and oranges to compare the pixel count of two imaging systems directly.

 

| Kevin Wheatley

| Senior Do-er of Technical Things

| Cinesite (Europe) Ltd

style="margin-top:0; margin-bottom: 0;">| These are the opinions of nobody and are not shared by my employers |

 


Kevin Wheatley wrote :

 

class="style9" >Cineon systems use the following sizes (pixels across the 35mm frame >x lines per picture) : 4096 x 3112 - '4K' Full app 2096 x 1556 - '2K' Full >app

 

style="margin-top:0;">In the interest of crossing the 'T's, full app is 2048 x 1556.

Jake Morrison

Creative Director

Goat Consortium

http://www.goat.com

 


 

Jake Morrison wrote :

 

class="style9" >In the interest of crossing the 'T's, full app is 2048 x 1556.

 

style="margin-top:0;">Erm, yes, that would be a jet-lag typo ...

| Kevin Wheatley

| Senior Do-er of Technical Things ||

| Cinesite (Europe) Ltd |

 


 

 

 

 

 

 

 

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