Resolution question

[excessnoise]

I just got my 10D and took about 50 pics. Checking out the image size in PS I noticed that all my Large/Fine jpg's have a resolution (x,y) of 150. My Epson point/shoot (3.3 MP) on its next to highest res. was always 480. Just doesn't make sense to me (nothing unusual there). I thought you had to have res. of 250 and up to print clearly. Am I missing something?

[Dans_D60]

Check your default “Preferences” under the “Edit” menu. Or the settings in the RAW conversion program (if you are using RAW)
Dan
http://www.pettusphoto.com

ADOBE PS PREFERENCES

http://www.pettusphoto.com/preference.jpg

RAW CONVERSION APPLICATION

http://www.pettusphoto.com/convert.jpg

[lziering]

The DPI resolution that you set this up at is irrelivent. You will get the same number of total pixels with whatever setting you use. It will just display at a differnt size on the screen.

[excessnoise]

I haven't tried Raw yet due to problems people are having with BreezeBrowser 4 but 6.3MP is 6.3MP in the set size of the sensor. I don't know if it was 150 and 'document size' that was huge.
I was just concerned due that you can't add digital info (ie pixels) that aren't there. Res of 150 seemed low. ?

somewhat off the subject : regarding RAW. I just saw that Photoshop now has a RAW plug-in that will read RAW images. Maybe someone has already mentioned it but I haven't seen it here so I thought I'd bring it up.
Has anyone tried it?

Review: http://www.imaging-resource.com/EVENTS/PMAS03/1045632455.html

Adobe page: http://www.adobe.com/products/photoshop/cameraraw.html

Note it doesn't list 10D??? Kind of strange since it lists
EOS-1D
EOS-1Ds
EOS-D30
EOS-D60

[lziering]

To use Adobe Camera RAW for 10D images you will need to do a hack on the program (fairly simple and described on Fred Miranda's site). It is a great converter, has very intuitive controls, and is very, very fast.

http://www.fredmiranda.com/forum/topic/25906/0#220623

[excessnoise]

Thanks all

Iz... that FM link is dead. I'll search for it. (slow day at work)
I'm thinking of getting that plugin

[CyberDyneSystems]

hmmm... dead link,. maybe we need to be registered,. as I can't search either.

[excessnoise]

I registered and it still is File not found

Roger Cavanagh has the fix on his webpage:
http://www.rogercavanagh.com/helpinfo/15_acrpatch.htm
for PC. He also has one for Mac.
found it on FM site.

This post has made a definate left turn :-)

[daveh]

excessnoise wrote:
I was just concerned due that you can't add digital info (ie pixels) that aren't there. Res of 150 seemed low. ?


I think you're getting hung up on a mostly harmless/meaningless number. Whether it's 1 DPI or 100,000 DPI, you've still got the same image information. The DPI setting is just a hint to a page layout program as to what size you expect the image to be printed at.

Years ago I had a page layout program that cared too much about this number and I had someone who always sent me tiffs with very strange DPI numbers so I wrote a perl script that just hacked that number in each of his files to a number that worked better with my program. It made no change to the image but prevented that program from trying to print it across 6 pages ;)

[Roger_Cavanagh]

DPI only affects the physical print size not the pixels in the picture as several people have said. I've got a sgort article about this:

http://www.rogercavanagh.com/pstips/01.htm

Regards,

[Dans_D60]

Roger_Cavanagh wrote:
DPI only affects the physical print size not the pixels in the picture as several people have said. I've got a sgort article about this:

http://www.rogercavanagh.com/pstips/01.htm

Regards,



Hello Roger:

I agree … to a point. Programs like PS base calculations around document size. And rightfully so. However when people talk about 72 DPI for displays … that’s correct. Every pixel must be used when the computer and application algorithms “paint” an image on a CRT or LCD. The number of physical pixels ranges roughly from 72-96 pixels-per-inch. To display a non-altered and non-compressed image “as is” on a display with no pixel removal or additions, setting the DPI at 72 and disregard physical size is accurate and will “impedance match” the output. But for the majority of display programs, this would not make much sense. Again, I agree with your hypothesis that a 400X300 “pixel” image will display 400X300 no matter what the DPI and the size on “your” display will depend on physical dimensions and resolution settings. Nevertheless, the actual painting of pixels on the display will still occur at 72-96 DPI. Cannot make or remove physical pixels on the display.
My $.02 …. Dan
http://www.pettusphoto.com

[daveh]

Dans_D60 wrote:
To display a non-altered and non-compressed image “as is” on a display with no pixel removal or additions, setting the DPI at 72 and disregard physical size is accurate and will “impedance match” the output.

It's not really a display vs. printer thing - it's just that programs like web browsers ignore the DPI setting. (Both for displaying on-screen and printing.)

Setting the DPI to 72 has no effect. Web browsers just ignore it. However, if your graphic editing software and/or your mind is heavily DPI-based, then setting the DPI to 72 may make you and/or your software more comfortable.

[Dans_D60]

daveh wrote:
Dans_D60 wrote:
To display a non-altered and non-compressed image “as is” on a display with no pixel removal or additions, setting the DPI at 72 and disregard physical size is accurate and will “impedance match” the output.

It's not really a display vs. printer thing - it's just that programs like web browsers ignore the DPI setting. (Both for displaying on-screen and printing.)

Setting the DPI to 72 has no effect. Web browsers just ignore it. However, if your graphic editing software and/or your mind is heavily DPI-based, then setting the DPI to 72 may make you and/or your software more comfortable.

Dave:

Fair enough – again – for the most part. But sometimes the physical constraints do enter into the picture …. Here is a link to a rudimentary article from the University of Wisconsin Information Systems Department: http://wiscinfo.doit.wisc.edu/ltde/ORFI/wds/Print/exporting.htm

OK … enough said!
Dan
http://www.pettusphoto.com

[daveh]

Physical constraints apply to printers and displays. CRTs are about as flexible as Inkjets in terms of their fundamental ability to change their feature size (though the range is different). LCDs are less flexible.

When the user wants an image of a certain size that doesn't match the output resolution (display or printer), then the software reasmples it. However, current web browsers simply don't resample (by default) on screen. The web standard is that images are mapped 1:1 on the screen. Some common graphics formats don't even have a DPI setting which is probably why this is the case. (There's also an option in IE and some other browsers to automatically resample images that are wider than the browser window. This is totally dependent on the window size, not screen resolution, DPI setting of the file etc.)

Interestingly, when you print from a web browser, then it DOES resample, but it resamples from the display DPI to the printer DPI. It still doesn't look at the DPI tag in the file.

The article you mentioned is really a little too rudimentary. For example, telling a user to scan for the web at 72DPI makes the assumption that exactly matching the original printed size is more important than capturing the original information. Such advice can save a beginner from putting a 4800 dpi scan on the web but an intermediate web page maker might realize that he needs to scan at say 200 dpi to produce a readable scan. The viewer may have to scroll if the image is large but at least it will be readable.