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Digital Rebel and .JPG size

 
 
jk
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      11-08-2004
Be patient with me. Here's my problem with my brand new camera. I need
fairly small pics of things that I put up on Ebay. At the smallest auto
setting on my Rebel, the pix are roughly 500,000 kb and resolution 150
pixels/in. These are way to big and thus slow to load. If I edit them down
to about 4" wide, they only get down to about 300,000kb. I'm not
knowledgable enough to figure out exactly what to change to achieve good
quality, but make them smaller at the same time. I notice that as I bring
the resolution down, the pixel demensions go down but the image size stays
the same? Can someone either point me to a tutorial, or explain the
relationship between these settings? Is there a camera setting that will
enable me to take alot of pictures and minimize the editing? Thanks!

--
JK Sinrod
Sinrod Stained Glass Studios
www.sinrodstudios.com
Coney Island Memories
www.sinrodstudios.com/coneymemories


 
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Charles Schuler
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      11-08-2004

"jk" <(E-Mail Removed)> wrote in message
news:TzRjd.45989$(E-Mail Removed). net...
> Be patient with me. Here's my problem with my brand new camera. I need
> fairly small pics of things that I put up on Ebay. At the smallest auto
> setting on my Rebel, the pix are roughly 500,000 kb and resolution 150
> pixels/in. These are way to big and thus slow to load. If I edit them down
> to about 4" wide, they only get down to about 300,000kb. I'm not
> knowledgable enough to figure out exactly what to change to achieve good
> quality, but make them smaller at the same time. I notice that as I bring
> the resolution down, the pixel demensions go down but the image size stays
> the same? Can someone either point me to a tutorial, or explain the
> relationship between these settings? Is there a camera setting that will
> enable me to take alot of pictures and minimize the editing? Thanks!


You have a couple of ways to go. You can change the camera resolution via
the MENU button. Quality is the top choice on the first menu and you can
select from among 7 choices.

Also, you can use Photoshop Elements (bundled with your camera) to change
size and resolution.


 
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fortknight
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      11-08-2004
jk wrote:
> Be patient with me. Here's my problem with my brand new camera. I need
> fairly small pics of things that I put up on Ebay. At the smallest auto
> setting on my Rebel, the pix are roughly 500,000 kb and resolution 150
> pixels/in. These are way to big and thus slow to load. If I edit them down
> to about 4" wide, they only get down to about 300,000kb. I'm not
> knowledgable enough to figure out exactly what to change to achieve good
> quality, but make them smaller at the same time. I notice that as I bring
> the resolution down, the pixel demensions go down but the image size stays
> the same? Can someone either point me to a tutorial, or explain the
> relationship between these settings? Is there a camera setting that will
> enable me to take alot of pictures and minimize the editing? Thanks!
>


There are two measurements for images. The raw number of rows and
columns of image pixels. like 640x480. And there is the intended
width and height of the image. Like 8x10, or 5x7. The combined method
is PPI which is the number of pixels that would be in a row 1 inch long.

Some programs use primarally just the raw number (like image editors),
some use the intended size (like publishing programs). And depending on
the HTML sometimes the image will display pixel per pixel on the screen,
and sometimes based on the "width" of the image and will scale up or down.

Generally you will get the best results by setting your image to 72DPI,
and setting the width to 4" (In this case this would get your images
about 1/4 smaller). This may be small enough.
 
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Gisle Hannemyr
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      11-08-2004
"jk" <(E-Mail Removed)> writes:
> Be patient with me. Here's my problem with my brand new camera. I
> need fairly small pics of things that I put up on Ebay. At the
> smallest auto setting on my Rebel, the pix are roughly 500,000 kb
> and resolution 150 pixels/in. These are way to big and thus slow to
> load. If I edit them down to about 4" wide, they only get down to
> about 300,000kb. I'm not knowledgable enough to figure out exactly
> what to change to achieve good quality, but make them smaller at the
> same time. I notice that as I bring the resolution down, the pixel
> demensions go down but the image size stays the same? Can someone
> either point me to a tutorial, or explain the relationship between
> these settings?


Assuming you're using Photoshop or Photoshop Elements to resize,
the main setting you are interested in is "Pixel Dimensions".

Do the following:
- Set "Pixel Dimensions" to 450 x 300 pixels.
- Ignore "Resolution".
- Tick "Resample Image" and select "Bicubic".

For more background, take a look at:
http://heim.ifi.uio.no/~gisle/photo/pixels.html
(in particular Q14).
--
- gisle hannemyr [ gisle{at}hannemyr.no - http://folk.uio.no/gisle/ ]
================================================== ======================
When you say you live in the real world, which one are you referring to?
 
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BillyJoeJimBob
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      11-09-2004
Gisle Hannemyr wrote:

>
> Assuming you're using Photoshop or Photoshop Elements to resize,
> the main setting you are interested in is "Pixel Dimensions".
>
> Do the following:
> - Set "Pixel Dimensions" to 450 x 300 pixels.
> - Ignore "Resolution".
> - Tick "Resample Image" and select "Bicubic".


Yeah, what he said, though I was going to suggest 600x400 instead
of 450x300.

Save as JPEG with a quality of around 6 or 7. You should easily
end up with filesizes under 100k... probably somewhere between
60k and 70k. If you go to 450x300 instead of 600x400, you will
probably end up with filesizes down arounnd 50k.

BJJB


 
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jk
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      11-09-2004
I'm using Paintshop Pro 8.0 It's much less complicated. So you all think
I should reduce the size using pixel control instead of resolution? I have
the camera set at the lowest quality now, and the res is 150. Maybe there's
a manual control on the camera for a reduced setting?

--
JK Sinrod
Sinrod Stained Glass Studios
www.sinrodstudios.com
Coney Island Memories
www.sinrodstudios.com/coneymemories


 
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Gisle Hannemyr
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      11-09-2004
"jk" <(E-Mail Removed)> writes:
> I'm using Paintshop Pro 8.0 It's much less complicated. So you all
> think I should reduce the size using pixel control instead of
> resolution?


Yes!

> I have the camera set at the lowest quality now,


At its lowest quality, the file size from the dRebel is
1536x1024 pixels. This is much more than is suitable for
web publication (which is 450x300 or 600x400 pixels).

You can't produce images suitable for the web /directly/ from a
dRebel (if you want web-quality from your camera, ditch your
dRebel and buy a $30 webcam).

Forget about getting web-sized files from the camera. Reset your
camera to give you the /highest quality/. That gives you the best
starting point for reducing the size in PSP.

> and the res is 150. Maybe there's a manual control on the camera for
> a reduced setting?


The resolution setting of your camera is meningless in this context.

I've tried to clarify these things in the follwing note:
http://heim.ifi.uio.no/~gisle/photo/pixels.html
Please read it and let me know if it cleared up things.
--
- gisle hannemyr [ gisle{at}hannemyr.no - http://folk.uio.no/gisle/ ]
================================================== ======================
When you say you live in the real world, which one are you referring to?
 
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Dave Herzstein
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      11-09-2004
jk wrote:
>
> I'm using Paintshop Pro 8.0 It's much less complicated. So you all think
> I should reduce the size using pixel control instead of resolution? I have
> the camera set at the lowest quality now, and the res is 150. Maybe there's
> a manual control on the camera for a reduced setting?


The "res" (or DPI, or PPI) is meaningless for a web display- its the
pixel dimensions that count. Resize the image to between 400 and 500
pixels on the long side for an ebay display.

-Dave
 
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jk
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      11-09-2004

"Gisle Hannemyr" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> "jk" <(E-Mail Removed)> writes:
> > I'm using Paintshop Pro 8.0 It's much less complicated. So you all
> > think I should reduce the size using pixel control instead of
> > resolution?

>
> Yes!
>
> > I have the camera set at the lowest quality now,

>
> At its lowest quality, the file size from the dRebel is
> 1536x1024 pixels. This is much more than is suitable for
> web publication (which is 450x300 or 600x400 pixels).
>
> You can't produce images suitable for the web /directly/ from a
> dRebel (if you want web-quality from your camera,


Thanks Giselle! In PSP 8, when I change the pixel size or print size they
both proportionally changed..... but when I change the resolution, only the
pixel size changes and the print size remains the same. So I can lower the
res to reduce the pixel size, or reduce the pixel size which will reduce the
print size. Which method will reduce the file size more? It's a bit
confusing, thanks for your patience.

--
JK Sinrod
Sinrod Stained Glass Studios
www.sinrodstudios.com
Coney Island Memories
www.sinrodstudios.com/coneymemories


 
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Michael A. Covington
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      11-09-2004
"jk" <(E-Mail Removed)> wrote in message
news:yBckd.54571$(E-Mail Removed). net...

>
> Thanks Giselle! In PSP 8, when I change the pixel size or print size they
> both proportionally changed..... but when I change the resolution, only
> the
> pixel size changes and the print size remains the same. So I can lower the
> res to reduce the pixel size, or reduce the pixel size which will reduce
> the
> print size. Which method will reduce the file size more? It's a bit
> confusing, thanks for your patience.


Changing the resolution in dots per inch, without resampling the pixels,
does not change the file size at all.

Changing the number of pixels is called resampling and is what you want to
do. Bear in mind that when you do it, you are throwing away information --
you cannot enlarge the image later and get back the details you lost.


 
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