Velocity Reviews - Computer Hardware Reviews

Velocity Reviews > Newsgroups > Computing > Digital Photography > size of a raw images - comparison?

Reply
Thread Tools

size of a raw images - comparison?

 
 
John
Guest
Posts: n/a
 
      06-16-2008
Hi,
Can any one tell me how the size of raw image computed?

say VGA - 640x480?

How may bytes will be one full frame?

how much will be the size of each pixel?

How many pixels constitutes one full line in the frame?

How different is it for foveon cameras?

How much bytes will each line of the frame contain and what will be
the
pixel size in foveon cameras and ordinary cameras

Regards,
Jm

 
Reply With Quote
 
 
 
 
David J Taylor
Guest
Posts: n/a
 
      06-16-2008
John wrote:
> Hi,
> Can any one tell me how the size of raw image computed?
>
> say VGA - 640x480?
>
> How may bytes will be one full frame?


Typically:
12 bits x 640 x 480

> how much will be the size of each pixel?


12 bits, as it contains only one colour

> How many pixels constitutes one full line in the frame?

640, but they will be 320 R + 320 G, or 320 B + 320 G pixels

> How different is it for foveon cameras?
>
> How much bytes will each line of the frame contain and what will be
> the
> pixel size in foveon cameras and ordinary cameras
>
> Regards,
> Jm


I hope that helps somewhat. I don't know how many bits Foveon uses, but
it records an RGB value at each pixel - but it does not have as many
pixels as a Bayer camera.

Cheers,
David


 
Reply With Quote
 
 
 
 
ben brugman
Guest
Posts: n/a
 
      06-16-2008

>
> Typically:
> 12 bits x 640 x 480
>

Not all Raw is 12 bits.
Typically Raw is compressed.

Example for Nikon
Size of the raw is 3037 x 2012.
One day,
Smallest 4785KB
Largest 7106KB
Average 5408KB

Average is pretty stable. (Works out to 0.9 byte for each pixel).

Ben
 
Reply With Quote
 
David J Taylor
Guest
Posts: n/a
 
      06-17-2008
ben brugman wrote:
>> Typically:
>> 12 bits x 640 x 480
>>

> Not all Raw is 12 bits.
> Typically Raw is compressed.
>
> Example for Nikon
> Size of the raw is 3037 x 2012.
> One day,
> Smallest 4785KB
> Largest 7106KB
> Average 5408KB
>
> Average is pretty stable. (Works out to 0.9 byte for each pixel).
>
> Ben


Thanks, Ben. I was trying to give a first-cut answer to demonstrate the
principles, so it's helpful to have your input as well. I know that Nikon
offers both lossless and lossy compression as well. What sort are you
using for the figures above?

Cheers,
David


 
Reply With Quote
 
nospam
Guest
Posts: n/a
 
      06-17-2008
In article <61s5k.10332$(E-Mail Removed)> , David J
Taylor <(E-Mail Removed)-this-bit.nor-this-bit.co.uk>
wrote:

> > How different is it for foveon cameras?
> >
> > How much bytes will each line of the frame contain and what will be
> > the
> > pixel size in foveon cameras and ordinary cameras
> >

> I hope that helps somewhat. I don't know how many bits Foveon uses, but
> it records an RGB value at each pixel - but it does not have as many
> pixels as a Bayer camera.


sigma uses a12 bit a/d converter, then it goes through a funky lookup
table that scales the data and applies some sort of colour conversion,
and then it's lossy compressed (sigma calls it 'nearly lossless').

it's not exactly 'raw.'
 
Reply With Quote
 
David J Taylor
Guest
Posts: n/a
 
      06-17-2008
nospam wrote:
[]
> sigma uses a12 bit a/d converter, then it goes through a funky lookup
> table that scales the data and applies some sort of colour conversion,
> and then it's lossy compressed (sigma calls it 'nearly lossless').
>
> it's not exactly 'raw.'


Half-baked?

David


 
Reply With Quote
 
nospam
Guest
Posts: n/a
 
      06-17-2008
In article <NaJ5k.10737$(E-Mail Removed)> , David J
Taylor <(E-Mail Removed)-this-bit.nor-this-bit.co.uk>
wrote:

> > it's not exactly 'raw.'

>
> Half-baked?


the file format isn't the only thing about the sigma cameras can be
considered 'half-baked.'
 
Reply With Quote
 
Chris H
Guest
Posts: n/a
 
      06-17-2008
In message
<(E-Mail Removed)>,
John <(E-Mail Removed)> writes
>Hi,
> Can any one tell me how the size of raw image computed?
>
> say VGA - 640x480?


Cameras that give RAW format(s) are generally a lot higher than VGA

> How may bytes will be one full frame?

Difficult there are several frame sizes used on "35mm" DSLRs and it
depends on the MP of the camera

http://en.wikipedia.org/wiki/RAW_image_format

http://www.tidalwave.it/infoglueDeli...?siteNodeId=18
6&languageId=1&contentId=-1#1.1

--
\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
\/\/\/\/\ Chris Hills Staffs England /\/\/\/\/
\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/



 
Reply With Quote
 
John
Guest
Posts: n/a
 
      06-19-2008
Why 12 bits? isnt it 36 bits for all the 3 colors?


Why only 2 colors in 640? i thought it should be 640/3 r, 640/3 g,
640/3 blue


The image is not raw probably its processed after goin through a a/d.


Regards,
jo


On Jun 16, 4:21 pm, "David J Taylor" <(E-Mail Removed)-
this-bit.nor-this-bit.co.uk> wrote:
> John wrote:
> > Hi,
> > Can any one tell me how the size of raw image computed?

>
> > say VGA - 640x480?

>
> > How may bytes will be one full frame?

>
> Typically:
> 12 bits x 640 x 480
>
> > how much will be the size of each pixel?

>
> 12 bits, as it contains only one colour
>
> > How many pixels constitutes one full line in the frame?

>
> 640, but they will be 320 R + 320 G, or 320 B + 320 G pixels
>
> > How different is it for foveon cameras?

>
> > How much bytes will each line of the frame contain and what will be
> > the
> > pixel size in foveon cameras and ordinary cameras

>
> > Regards,
> > Jm

>
> I hope that helps somewhat. I don't know how many bits Foveon uses, but
> it records an RGB value at each pixel - but it does not have as many
> pixels as a Bayer camera.
>
> Cheers,
> David


 
Reply With Quote
 
David J Taylor
Guest
Posts: n/a
 
      06-19-2008
John wrote:
> Why 12 bits? isnt it 36 bits for all the 3 colors?


Each pixel senses only /one/ colour.
>
> Why only 2 colors in 640? i thought it should be 640/3 r, 640/3 g,
> 640/3 blue


The classic Bayer pattern has twice as many green as red or blue, to
improve resolution and snr.

> The image is not raw probably its processed after goin through a a/d.
>
>
> Regards,
> jo


That depends to which camera you are referring. Some process more than
others.

David


 
Reply With Quote
 
 
 
Reply

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Preferred Size, Minimum Size, Size Jason Cavett Java 5 05-25-2008 08:32 AM
mega pixels, file size, image size, and print size - Adobe Evangelists Frank ess Digital Photography 0 11-14-2006 05:08 PM
[Maxxum 7D] Dimage RAW Viewer v. Adobe Raw Plugin Alan Browne Digital Photography 3 03-12-2005 04:17 AM
Adobe PS RAW convertor vs Nikon RAW convertor Vlad Gunko Digital Photography 8 01-25-2005 07:43 PM
How raw is RAW format? Editor www.nutritionsoftware.org Digital Photography 4 12-22-2003 07:33 PM



Advertisments