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Old Dec 14, 2005, 6:18 PM   #1
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I have the sony f 828, I have noticed the exif data on some of the pictures have 72 dpi vs some that are 300dpi. it seems more related to what I shot, vs what I edited thorught photoshop cs. Is it a setting in my camera??? I always shoot at 8mp
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Old Dec 14, 2005, 7:23 PM   #2
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Nothing to worry about. DPI and/or PPI is just how far apart the dots or pixels are. What matters is the pixel dimensions; in the F828's case they are 3264 x 2448 when at the 8MP setting. When you're printing an image, you want at least 200dpi, but 72ppi is the most you'll need to display on a monitor.
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Old Dec 14, 2005, 7:49 PM   #3
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but just to clarify... if i only have 72 dpi, the picture will not be enough when printed 8x 10...and how or wqhy are some events shot in 300 vs others in 72? i must be missing something?


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Old Dec 14, 2005, 7:51 PM   #4
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dpi has no meaning whatsoever until you print when it can (depending on software) determine the size of the print. Ignore it until then.
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Old Dec 15, 2005, 10:24 AM   #5
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I agree with others that you shouldn't worry about it until you want to print.

But it is odd. My guess is that some software that you're using is changing the DPI. I know that when I open up something in Photoshop I have it set to change the DPI to 250. But the camera uses 72 when it creates the image.

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Old Dec 15, 2005, 7:42 PM   #6
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that is what gets me, because lets face it, at the end of the day, a great picture ain't worth anything if you cannot print it right? And that is where I get frustrated, because I am not sure where the dpi changed. How do I set it in photoshop? I use cs....and never save my edited photos as the same name, so to me (as far as I remember) the pictures were not edited, or whatever, though they may have been looked at and even attempted (editing attempted, later cancelled etc) ...does what I am talking about make more sense?

thanks to everyone for their replies so far!!!
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Old Dec 15, 2005, 8:37 PM   #7
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after my lastest post, I played abit in photoshop cs, and I changed a picture from 72 to 300, and the picture bacame huge... and looked great... so I figure, it must be my camera taking the picture at 72 dpi, ...now when printing it or editing it, how should I worry about dpi? Or am I just not "getting it"

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Old Dec 15, 2005, 9:17 PM   #8
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You're not getting it.

DPI is Dots Per Inch, as in dots on the paper. Each pixel on the paper is one dot.

So, if you have an image that is 720 pixels high, if you print it at 72 Dots Per Inch it will put 72 of those pixels in every inch, and therefore print 10 inches tall.

If you were to take the image into Photoshop, go into image size and turn off "resample image", you can change the dpi to 300. You'll notice that the image is still 720 pixels high, but the size in inches shrinks. Now when you print it, it will put 300 pixels into an inch, and therefore print at about 2.5 inches tall.

When you resized your image before in Photoshop, you had "resample image" on, and therefore it increased the number of pixels when you increased the dpi in order to make it print at the same size. It did not increase the detail or quality of the image, but it does smooth out the pixelization you would see when zoomed in very close. You would typically only do this for extreme enlargements.


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Old Dec 15, 2005, 9:20 PM   #9
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To illustrate what I mean, try printing this 72 dpi image:


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Old Dec 15, 2005, 9:21 PM   #10
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And this 300 dpi version of the same image at the same pixel resolution:


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