Rebel XT Image DPI

[Matthew]

Hey all.

I just got back from New Orleans a few weeks ago and have lots of images that I really, really enjoy seeing. However, one problem I have is that the dpi on the images is only 72. I could swear I've seen files off of 350's that have 300 and 600dpi. What gives? Can I change this?

I'm not talking raw format, I'm talking jpg.

[timmciglobal]

DPI has nothing to do with images its based on what your viewing it on.

A monitor can't display 300 DPI so it doesn't at full view. DPI just says "display 72 pixels per inch" or "display 300 pixels per inch" 300 is what your images will most likly be printed out if you bring them to a photo lab, in adobe you can resize it to 300 DPI to get a "feel" for how big your image is (or just devise on your own)

8 megapixels = 300 dpi @ 8X10 basically (little bigger)

Tim

[Matthew]

I know, I'm talking about for print resolution, for which 300dpi is minimum. I can easily convert it in photoshop, but I'd rather not have to - my friend's nikon d50 takes shots in jpg format at 600 dpi... why can't i with my xt?

[Chucko]

I know, I'm talking about for print resolution, for which 300dpi is minimum.

Oh really? Are you printing on microchips? ;)

I read recently that 300 PPI (pixels per inch) should be considered a maximum for use with an inkjet printer, because above that the detail gets lost in the conversion to ink dots anyway. And consider that the average glossy magazine is printed at 150 DPI or less!

The other question is, is your technique good enough that your images have more than 300 PPI worth of resolution? Sometimes my images are that sharp, but not as often as I'd like, and I know it's not the equipment at fault.

I have gotten good results from resolutions as low as 150 PPI on 8.5" x 11" prints. If the image has adequate contrast, and you have skillfully used the sharpening tools at your disposal, that is plenty of resolution for printing.

Any decent photo editing software will allow you to change the PPI number to whatever you think is appropriate. This isn't resizing the image so much as redistributing the same pixels in a larger or smaller area.

[aparmley]

You need to understand something about image size. Take a camera with a sensor of say the rebel XT 3456x2304 and resolve it to 72 DPI you get an image size of 32" x 48" - meaning if you were to print a standard XT image at 32" x 48", thats 4 foot long by nearly three feet wide, you'd get a print at 72 DPI. resize that image down to a 6x4 [4x6] and you have an image that is 576 DPI. as Timmy stated at 8x10 thats approx 300 DPI. Don't believe me, open up a reg JPG from the XT in a photoshop application, click on view > rulers. I'll be darned if it opens up to another size that 32x48 at 72 DPI. No go to image>image size and uncheck resample image at the bottom. Now change the resolution to say 300, watch the dimesions change you get an image thats nearly 8x11, change it to 600 and you get an image a shade smaller than 4x6. . .

[cdifoto]

For what it's worth, I've printed 20x30 inch prints at about 115 DPI with excellent results.

[Alnath]

Hey all.

I just got back from New Orleans a few weeks ago and have lots of images that I really, really enjoy seeing. However, one problem I have is that the dpi on the images is only 72. I could swear I've seen files off of 350's that have 300 and 600dpi. What gives? Can I change this?

I'm not talking raw format, I'm talking jpg.

My 350D images are 72DPI and my G6 Images are 180DPI

[mediyoga]

I had the same problem with my sony F 828 for a book I worked on . I shot at max res and the guy at the printers said that it was only 72 dpi and my shots were a waste. I printed the necessary ones at a studio and rescanned them for the book.
hope this helps
Krishna Raman

[timmciglobal]

I think the concept your not understanding is if you use a proper printing application it'll print it at "Whatever" DPI you want. If you print the XT images on a 4x6 as stated the'll be "up to" 571 DPI printer limited. If you print them 8x10 the'll be about 300 dpi.

Tim

[timmciglobal]

Your printer is a complete moron then.

"resolution" in terms of megapixels = Total square inches X DPI^2

4X6 = 24 square inches. You want "300 dpi" thats 300X300= 90,000. 90,000 X 24 = 2,160,000 AKA 2.1 megapixels.

8x10 = 80 square inches. You want "300 dpi" thats 300X300=90,000. 90,000 X 80 = 7,200,000 aka 7.2 megapixels.

Tim