Velocity Reviews - Computer Hardware Reviews

Velocity Reviews > Newsgroups > Computing > Digital Photography > Size of the digital photo

Reply
Thread Tools

Size of the digital photo

 
 
Alan
Guest
Posts: n/a
 
      09-23-2003
Is the size of the photo equals the number of resolutions of the digital
camera if I use the maximun resolution ?
eg. I have a 5 Megapixels camera and take the photos at its max resolution,
then the photo memory size will be 5 MB ?


 
Reply With Quote
 
 
 
 
ThomasM
Guest
Posts: n/a
 
      09-23-2003

"Alan" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> Is the size of the photo equals the number of resolutions of the digital
> camera if I use the maximun resolution ?
> eg. I have a 5 Megapixels camera and take the photos at its max

resolution,
> then the photo memory size will be 5 MB ?
>


No, it depends on the level of compression the camera applies to the image
and on the complexity of the image. My G3 outputs 4MP JPGs at around 1.2-2.2
MB and RAWs at around 3.5 MB.

/ThomasM


 
Reply With Quote
 
 
 
 
Tom Thackrey
Guest
Posts: n/a
 
      09-24-2003


On 23-Sep-2003, "Alan" <(E-Mail Removed)> wrote:

> Is the size of the photo equals the number of resolutions of the digital
> camera if I use the maximun resolution ?
> eg. I have a 5 Megapixels camera and take the photos at its max
> resolution,
> then the photo memory size will be 5 MB ?


No, It takes 3 or 6 bytes to store a pixel (in most formats), so a 5
megapixel image would be 15 or 30 megabytes uncompressed. If compression is
used that number is reduced and no longer related directly to the resolution
of the image.
--
Tom Thackrey
www.creative-light.com
 
Reply With Quote
 
Jim Townsend
Guest
Posts: n/a
 
      09-24-2003
Alan wrote:

> Is the size of the photo equals the number of resolutions of the digital
> camera if I use the maximun resolution ?
> eg. I have a 5 Megapixels camera and take the photos at its max resolution,
> then the photo memory size will be 5 MB ?


Megapixels and Megabytes are two different things. A pixel is a representation
of a tiny portion of a picture.. (A picture-element.. or pix-el for short)

One pixel does not equal one byte. It takes several bytes to make up one
pixel. These bytes hold the values for the color and luminance information
that the pixel represents.

Not only that.. But there is a fair bit of extra information held in images
that is also made up of pixels. There is a header that defines the format that
the file is saved as. (JPEG, TIFF etc). Cameras also add EXIF information
which includes camera settings, date, user comments etc.. In some cases a
thumbnail of the image can actually be embedded in the header as well..

In uncompressed form, a 5MP camera would produce a file that's around 15 MB.

JPEG compression can bring that down to around 2 MB


 
Reply With Quote
 
Ron Hunter
Guest
Posts: n/a
 
      09-24-2003
Alan wrote:

> Is the size of the photo equals the number of resolutions of the digital
> camera if I use the maximun resolution ?
> eg. I have a 5 Megapixels camera and take the photos at its max resolution,
> then the photo memory size will be 5 MB ?
>
>

No, it will be more like 15 MB. Usually 3 bytes are required to store
each pixel.

 
Reply With Quote
 
Alan
Guest
Posts: n/a
 
      09-24-2003
Thank you all, I learned something from you.


 
Reply With Quote
 
Juan R. Pollo
Guest
Posts: n/a
 
      09-24-2003
Wow, I can't believe that went so smooth. Hard to find any topic that
doesn't turn into a flame war.

Juan

"Alan" <(E-Mail Removed)> wrote in message
news:3f7112ae$(E-Mail Removed)...
> Thank you all, I learned something from you.
>
>


 
Reply With Quote
 
Glyn Williams
Guest
Posts: n/a
 
      09-24-2003
"Ron Hunter" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...

> No, it will be more like 15 MB. Usually 3 bytes are required to store
> each pixel.



15 MB would be correct if you are storing each pixel as 8bits of Red Green and Blue. Of
course the normal CCD camera records nothing like this much information. Each CCD imaging
sensor (pixel) stores just a single brightness value. Either 12 or 8 bits. After this is
recorded, the colour information is computed from interpolating between adjacent red,
green or blue filtered elements.

This means that in (non foveon) cameras - two thirds of the "raw" data is invented by the
camera.

So really 5MP=5MB isnt totally innaccurate after all.

GW







 
Reply With Quote
 
EF in FL
Guest
Posts: n/a
 
      09-24-2003
> Wow, I can't believe that went so smooth. Hard to find any topic that
> doesn't turn into a flame war.
>


And what do you mean by that?! Trying to start trouble???

hehe j/k



 
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
"rec.photo.digital.txt" and "rec.photo.digital.dat" Filter DataUpdated and Posted SMS 斯蒂文• 夏 Digital Photography 1 11-26-2007 04:29 PM
Labelling prints in galleries: "photo" vs "digital photo" vs "digital manipulation"... Alan Justice Digital Photography 2 06-08-2005 03:10 PM
Re: goodbye rec.photo.digital -hello rec.photo.digital.slr-systems? Woodchuck Bill Digital Photography 36 10-30-2004 11:50 PM
Re: goodbye rec.photo.digital -hello rec.photo.digital.slr-systems? Woodchuck Bill Digital Photography 15 10-27-2004 04:29 AM
Digital Photography RFD: rec.photo.digital.slr vs rec.photo.digital.slr-systems? Lionel Digital Photography 16 09-17-2004 12:48 PM



Advertisments