Thursday, January 18, 2007
January/February 2006 HelpLine
Q) I hope you don't mind two bonehead questions at once. My first question is about dpi. I've been told by a Nikon user that I should set my camera's dpi to 300, but I can't find anything to set dpi in any of the camera menus or in the manual that came with the camera. Do you know of a way to set dpi in a camera? I usually shoot RAW.
A) Your questions are not bonehead (unless you're saying that you're asking a bonehead to answer the questions...hmm). Let me tackle them one at a time.
Camera dpi (dots per inch) or ppi (pixels per inch) can't be changed in your camera (the two terms are used interchangeably, though technically, ppi is the correct term for images). It's a measure of how far apart pixels are and has nothing to do with image quality except when paired with a specific output. The camera does set a parameter in the metadata to a specific dpi or ppi, but that's just metadata (instructions about the file) and doesn't affect the image that the camera captures.
If you process your image in an image editor, you can adjust your ppi there (particularly, in Adobe Camera Raw). The ppi setting only relates to your output. The camera simply gives you a certain number of total pixels, such as 2048 x 3072. If you could set your camera to 300 dpi, it would still output those 2048 x 3072 pixels. The only time you'd need to worry about the camera's dpi setting is if you took your media card directly to some output device that used ppi directly.
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