Go Back   Steve's Digicams Forums > Digicam Help > General Discussion

Reply
 
Thread Tools Search this Thread
Old Mar 12, 2005, 11:38 AM   #1
Junior Member
 
Join Date: Mar 2005
Posts: 1
Default

Hi there...

I have had a digital camera for several years, every year upgrading by a megapixel or so. I've got some great shots throughout my travels and such, but I was just noticing as I was going to edit some of these in photoshop to print out, that nothing has ever been shot in 300dpi despite using the highest settings (L and Superfine) in the camera. Is there not a way to have a picture in 300dpi? Why is it always 180dpi? and I'm looking to purchase a digital SLR, which worries me if Canon cannot produce shots in 300dpi for print.

Thanks for your input!
theglobetrotter is offline   Reply With Quote
Sponsored Links
Old Mar 12, 2005, 3:43 PM   #2
Senior Member
 
BillDrew's Avatar
 
Join Date: Jun 2002
Location: Hay River Township, WI
Posts: 2,512
Default

The image is X pixels wide and Y pixels high. Given those values, the dpi tells your printer how large to print the image. dpi has no meaning whatsoever until you print: it is just a number in the EXIF data. The only reason a camera puts a number there is that some software might gag if it is null.

Until you print, dpi has less to do with your photograph than your shoe size (larger feet mean more stability).
BillDrew is offline   Reply With Quote
Old Mar 12, 2005, 10:06 PM   #3
Senior Member
 
Join Date: Oct 2003
Location: Indian Rocks Beach, FL
Posts: 4,036
Default

To expand on what Bill said, one of my 5Mp cameras opens to 144 PPI in an image editor and the other to 72 PPI. They both give a 240 PPI 8 X 10 photo if I use all the pixels because the images have the same number of pixels. You just have to be careful you don't have "Resample" checked when you size it for print or it will keep the original PPI. But it has to dump pixels to do that.

The PPI it initially displays at is meaningless as he says. Look at your print size for 180 PPI, it should be a 14.4 X 10.8 inch image. If you wanted to make a 14.4 X 10.8 print it would come out 180 PPI. A smaller print would give a higher PPI and a larger print a smaller PPI. It is only 180 PPI if you print a 14.4 X 10.8 image.

slipe is offline   Reply With Quote
Old Mar 13, 2005, 8:36 AM   #4
Senior Member
 
BillDrew's Avatar
 
Join Date: Jun 2002
Location: Hay River Township, WI
Posts: 2,512
Default

Off topic, but that is the way these forums go:

The dpi vs ppi: slipe is closer to correct than I and globtrotter were in using ppi. I tend to take the chicken way out and use whichever the original poster used (dpi vs ppi), but I think neither really represents what is going on in a digicam very well. dpi doesn't really mean very much in terms digital (or chemical) photography at any stage of the processing. What is a "dot"? Dots can be seen clearly in newsprint images, but they certainly are not the picoliter bit of ink color printers put on paper.

Pixels have really clear meaning in terms of monitor display, but digicams (with exception of the Foveon) do not really have pixels. The pixels that are output (or post created from RAW files) are "averages" of several sensors with Red, Green, or Blue filters over them.

spm (Sensors Per Milimeter) would be a much better measure of digicam's image capturing. But no one uses that.
BillDrew is offline   Reply With Quote
 
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -5. The time now is 12:21 PM.