file size

[mcola]

Excuse this basic question which im sure has been asked before, but i can't
seem to find an answer anywhere else.
If my camera is set to a certain resolution, why are the resulting pictures
not all the same file size?
Thanks,
Mike

[nelly bly]

On 5/31/05 11:14 AM, in article , "mcola"
> wrote:

> Excuse this basic question which im sure has been asked before, but i can't
> seem to find an answer anywhere else.
> If my camera is set to a certain resolution, why are the resulting pictures
> not all the same file size?
> Thanks,
> Mike
>
>
Hi Mike,
The amount of detail, complexity, and color the camera is capturing in a
particular shot also helps to determine the file size.
Hth,
NB

[Rolf Egil Sølvik]

On Tue, 31 May 2005 11:14:54 -0400, "mcola"
> wrote:

>Excuse this basic question which im sure has been asked before, but i can't
>seem to find an answer anywhere else.
>If my camera is set to a certain resolution, why are the resulting pictures
>not all the same file size?

A non-compressed bitmap (where each pixel is "the same size" - i.e.
ten times the pixel count will give a filesize 10 times larger)
would be exactly the same size. For the format used in most
digicams, JPEG (.jpg), because it allows for different degrees of
(lossy) compression it will result in different resulting file
sizes. See http://www.photo.net/learn/jpeg/

[Mike Mills]

"mcola" > wrote in
:

> Excuse this basic question which im sure has been asked before,
> but i can't seem to find an answer anywhere else.
> If my camera is set to a certain resolution, why are the
resulting
> pictures not all the same file size?
Try this experiment.
take 3 pix at night trying to capture blackness, now put your hand
over the lens and shoot again.
check the filesizes.
Not all black is real black.
the agony of having 16 million colours!
As complexity rises the filesize rises too.
Now check over your biggest filesizes and look at the histogram
that is available in some viewers.
See how the energy is distributed across the colour bandwidth.

>

[All Things Mopar]

Rolf Egil Sølvik commented courteously...

> http://www.photo.net/learn/jpeg/

I pretty much understand JPEG, but this is still a great
article. Thanks.

--
ATM, aka Jerry

[mcola]

Thanks all for the replies. As I now understand it, ea. pic has diff.
degrees of complexity (pixel wise) and thus jpeg compression results in
differing final file size. But all pics taken at a certain resolution will
have the same number of pixels in raw format and thus the same sharpness
qualilty. Basic, but correct explanation? Thanks again, Mike

"mcola" > wrote in message
...
> Excuse this basic question which im sure has been asked before, but i
can't
> seem to find an answer anywhere else.
> If my camera is set to a certain resolution, why are the resulting
pictures
> not all the same file size?
> Thanks,
> Mike
>
>

[Charles Kerekes]

Mike,

Your summary is correct. I use a Canon camera and always use the raw
format (CRW files), and thus the file sizes are always the same.

Charlie

http://FlyingSamPhoto.com
Got digital photos? Show them off!

[Charles Schuler]

"mcola" > wrote in message
...
> Thanks all for the replies. As I now understand it, ea. pic has diff.
> degrees of complexity (pixel wise) and thus jpeg compression results in
> differing final file size. But all pics taken at a certain resolution
> will
> have the same number of pixels in raw format and thus the same sharpness
> qualilty. Basic, but correct explanation? Thanks again, Mike

Yes and to see how jpegs work, take a noisy picture (highest ISO and long
exposure) and you will often produce a larger file. The noise (fine
details) produced by the high ISO is more difficult to compress.