# Size of the digital photo

Discussion in 'Digital Photography' started by Alan, Sep 24, 2003.

1. ### AlanGuest

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 ?

Alan, Sep 24, 2003

2. ### ThomasMGuest

"Alan" <> wrote in message
news:...
> 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

ThomasM, Sep 24, 2003

3. ### Tom ThackreyGuest

On 23-Sep-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 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

Tom Thackrey, Sep 24, 2003
4. ### Jim TownsendGuest

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

Jim Townsend, Sep 24, 2003
5. ### Ron HunterGuest

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.

Ron Hunter, Sep 24, 2003
6. ### AlanGuest

Thank you all, I learned something from you.

Alan, Sep 24, 2003
7. ### Juan R. PolloGuest

Wow, I can't believe that went so smooth. Hard to find any topic that
doesn't turn into a flame war.

Juan

"Alan" <> wrote in message
news:3f7112ae\$...
> Thank you all, I learned something from you.
>
>

Juan R. Pollo, Sep 24, 2003
8. ### Glyn WilliamsGuest

"Ron Hunter" <> wrote in message
news:...

> 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

Glyn Williams, Sep 24, 2003
9. ### EF in FLGuest

> 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

EF in FL, Sep 24, 2003