Pixels / inch...

"Steve" <sjtnet@hotmail.com> wrote in message
news:uzdDwBDeFHA.2844@TK2MSFTNGP14.phx.gbl...

> OK, here is a very basic question that I can't quite seem to answer for
> myself.
>
> My camera can adjust the number of pixels captured (picture resolution?)

and

> the data compression setting (image fineness?), but what / when / how is

the

> number of pixels / inch set? I have a Canon A520 with a maximum resolution
> of 2272 x 1704 and all my images seem to get captured at 180 pixels /

inch.
Images aren't captured at any value of ppi, rather they are captured at a
specific number of horizontal pixels and vertical pixels. Somewhere your
camera has inserted 180 as the default. The pixels per inch value is only a
scale factor and has no importance.
Jim

Hi Jim, thanks for you input. OK, let's see if I got the gist of what you
just said.

So the 180 ppi value that I see when, for example I do "Image > Image
Information" in Paint Shop Pro, has been embedded in the meta data of the
image (by the camera firmware?), so that an application that opens the file,
can set the "rulers" or other "guides" in some meaningful way. Is this what
you are saying?

Steve


"Jim" <j.n@nospam.com> wrote in message
news:gzHue.1277$5w3.975@newssvr11.news.prodigy.com ...

>
> "Steve" <sjtnet@hotmail.com> wrote in message
> news:uzdDwBDeFHA.2844@TK2MSFTNGP14.phx.gbl...

>> OK, here is a very basic question that I can't quite seem to answer for
>> myself.
>>
>> My camera can adjust the number of pixels captured (picture resolution?)

> and

>> the data compression setting (image fineness?), but what / when / how is

> the

>> number of pixels / inch set? I have a Canon A520 with a maximum
>> resolution
>> of 2272 x 1704 and all my images seem to get captured at 180 pixels /

> inch.
> Images aren't captured at any value of ppi, rather they are captured at a
> specific number of horizontal pixels and vertical pixels. Somewhere your
> camera has inserted 180 as the default. The pixels per inch value is only
> a
> scale factor and has no importance.
> Jim
>
>

I'm not exactly sure where you are going
with this question but I'll try to offer some
ideas.

180 DPI is the Canon standard. Changing
the camera's compression settings or the
image size does not affect the DPI...this
would have to be accomplished with editing
software.

Your best bet is to set your camera for the
highest possible quality and if you require
smaller files for e-mail, etc...do it after the
files are safely downloaded onto your hard
drive. I suggest that copies of all original,
unedited image files should be saved on
removable media. It's good insurance...

Maybe the following article and some of
the links it contains will offer some insights:

DPI - Printer Resolution
http://tinyurl.com/wu5j

--

John Inzer
MS Picture It! MVP



"Steve" <sjtnet@hotmail.com> wrote in message
news:uzdDwBDeFHA.2844@TK2MSFTNGP14.phx.gbl...

> OK, here is a very basic question that I can't quite seem to answer for
> myself.
>
> My camera can adjust the number of pixels captured (picture resolution?)
> and the data compression setting (image fineness?), but what / when / how
> is the number of pixels / inch set? I have a Canon A520 with a maximum
> resolution of 2272 x 1704 and all my images seem to get captured at 180
> pixels / inch.
>
> Am I missing something? Or should I just start the weekend early in an
> attempt to get more R&R?
>
> Thanks, Steve
>

Hi John, thanks for the link to some very interesting & informative
articles.

I wasn't really "going" anywhere with the question. I'm very new to this
digital photographer / imaging stuff and I was simply trying to understand
the relationship between the myriad of often (for me anyway) confusing
acronyms.

My images have "EXIF Information" which states "X resolution 180.0 dpi" & "Y
resolution 180.0 dpi" and if I open the images in Paint Shop Pro the image
rulers are set to conform to the 180 dpi resolution. So this would be the
size of the printed image, if printed on a Canon printer. Is this what you
are saying when you state 180 dpi is the Canon standard.

Thanks for your patience, Steve


"John Inzer" <oobie@doobie.xyz> wrote in message
news:OXM%23XNFeFHA.4016@TK2MSFTNGP14.phx.gbl...

> I'm not exactly sure where you are going
> with this question but I'll try to offer some
> ideas.
>
> 180 DPI is the Canon standard. Changing
> the camera's compression settings or the
> image size does not affect the DPI...this
> would have to be accomplished with editing
> software.
>
> Your best bet is to set your camera for the
> highest possible quality and if you require
> smaller files for e-mail, etc...do it after the
> files are safely downloaded onto your hard
> drive. I suggest that copies of all original,
> unedited image files should be saved on
> removable media. It's good insurance...
>
> Maybe the following article and some of
> the links it contains will offer some insights:
>
> DPI - Printer Resolution
> http://tinyurl.com/wu5j
>
> --
>
> John Inzer
> MS Picture It! MVP
>
>
>
> "Steve" <sjtnet@hotmail.com> wrote in message
> news:uzdDwBDeFHA.2844@TK2MSFTNGP14.phx.gbl...

>> OK, here is a very basic question that I can't quite seem to answer for
>> myself.
>>
>> My camera can adjust the number of pixels captured (picture resolution?)
>> and the data compression setting (image fineness?), but what / when / how
>> is the number of pixels / inch set? I have a Canon A520 with a maximum
>> resolution of 2272 x 1704 and all my images seem to get captured at 180
>> pixels / inch.
>>
>> Am I missing something? Or should I just start the weekend early in an
>> attempt to get more R&R?
>>
>> Thanks, Steve
>>

>

If you go to the following website,
http://www.steves-digicams.com/
you can view and download sample
images from many different brands
and models of digital cameras.

If you view the EXIF data for the various
samples...you'll discover that Sony images
for example are 72DPI, Canon is 180DPI,
and Nikon is even 300DPI. However...
the image resolution size for size is
the same. IOW...a 4MP Sony image, a
4MP Canon image and a 4MP Nikon
image are all basically the same...
2217x1704. These images will all print
equally well.

If you go to this page...
http://www.steves-digicams.com/2005_...s_samples.html
you can download comparable shots
both from a "Canon S2 IS" and a "Sony H1"...
you will find that shot for shot ...they are
very similar even though the Canon DPI is
180 and the Sony DPI is 72.

Truth is, I guess I don't even understand
your question.

--

John Inzer
MS Picture It! MVP



"Steve" <sjtnet@hotmail.com> wrote in message
news:%23ufCRSHeFHA.2124@TK2MSFTNGP14.phx.gbl...

> Hi John, thanks for the link to some very interesting & informative
> articles.
>
> I wasn't really "going" anywhere with the question. I'm very new to this
> digital photographer / imaging stuff and I was simply trying to understand
> the relationship between the myriad of often (for me anyway) confusing
> acronyms.
>
> My images have "EXIF Information" which states "X resolution 180.0 dpi" &
> "Y resolution 180.0 dpi" and if I open the images in Paint Shop Pro the
> image rulers are set to conform to the 180 dpi resolution. So this would
> be the size of the printed image, if printed on a Canon printer. Is this
> what you are saying when you state 180 dpi is the Canon standard.
>
> Thanks for your patience, Steve

Hi John, well for someone who doesn't understand the question, you're doing
a pretty good job of answering it.

Truth is, maybe I wasn't sure exactly what I was asking. Unfortunately
that's a common bi-product of just "not knowing" but you've got to start
somewhere, right?

So it seems that the 72 / 180 / 300 DPI values are pretty much arbitrarily
set (by the camera manufacturer?) and don't have any impact on the "quality"
of the image. So, quality of image capture is all about resolution /
compression and quality of image printing is all about printer DPI
specification.

Thanks again for your help, Steve

"John Inzer" <oobie@doobie.xyz> wrote in message
news:%23w9SpZIeFHA.3616@TK2MSFTNGP09.phx.gbl...

> If you go to the following website,
> http://www.steves-digicams.com/
> you can view and download sample
> images from many different brands
> and models of digital cameras.
>
> If you view the EXIF data for the various
> samples...you'll discover that Sony images
> for example are 72DPI, Canon is 180DPI,
> and Nikon is even 300DPI. However...
> the image resolution size for size is
> the same. IOW...a 4MP Sony image, a
> 4MP Canon image and a 4MP Nikon
> image are all basically the same...
> 2217x1704. These images will all print
> equally well.
>
> If you go to this page...
> http://www.steves-digicams.com/2005_...s_samples.html
> you can download comparable shots
> both from a "Canon S2 IS" and a "Sony H1"...
> you will find that shot for shot ...they are
> very similar even though the Canon DPI is
> 180 and the Sony DPI is 72.
>
> Truth is, I guess I don't even understand
> your question.
>
> --
>
> John Inzer
> MS Picture It! MVP
>
>
>
> "Steve" <sjtnet@hotmail.com> wrote in message
> news:%23ufCRSHeFHA.2124@TK2MSFTNGP14.phx.gbl...

>> Hi John, thanks for the link to some very interesting & informative
>> articles.
>>
>> I wasn't really "going" anywhere with the question. I'm very new to this
>> digital photographer / imaging stuff and I was simply trying to
>> understand the relationship between the myriad of often (for me anyway)
>> confusing acronyms.
>>
>> My images have "EXIF Information" which states "X resolution 180.0 dpi" &
>> "Y resolution 180.0 dpi" and if I open the images in Paint Shop Pro the
>> image rulers are set to conform to the 180 dpi resolution. So this would
>> be the size of the printed image, if printed on a Canon printer. Is this
>> what you are saying when you state 180 dpi is the Canon standard.
>>
>> Thanks for your patience, Steve

>

Now you are getting it. Did you read the
message from Jim? I practically wrote a
book trying to explain what he said in a
couple of sentences.

In the case of the files you download from
your camera...the size is fixed regardless
of the DPI.

On the other hand...if you were scanning
an image. The DPI you choose...changes
the size of the file.

--

John Inzer
MS Picture It! MVP



"Steve" <sjtnet@hotmail.com> wrote in message
news:uJV$RKOeFHA.2700@tk2msftngp13.phx.gbl...

> Hi John, well for someone who doesn't understand the question, you're
> doing a pretty good job of answering it.
>
> Truth is, maybe I wasn't sure exactly what I was asking. Unfortunately
> that's a common bi-product of just "not knowing" but you've got to start
> somewhere, right?
>
> So it seems that the 72 / 180 / 300 DPI values are pretty much arbitrarily
> set (by the camera manufacturer?) and don't have any impact on the
> "quality" of the image. So, quality of image capture is all about
> resolution / compression and quality of image printing is all about
> printer DPI specification.
>
> Thanks again for your help, Steve