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Photography F.A.Q (Last Updated: 2024 Nov 13 3:04 pm)



Subject: Questions About Mega Pixels


TallPockets ( ) posted Mon, 25 April 2005 at 9:48 AM · edited Mon, 29 July 2024 at 4:06 PM

My sister just bought a 4 MegaPixel Samsung digital camera from a private party. It has four settings for quality. Her pictures kept coming to me at 96dpi resolutions even though she set her camera on the 'next to highest' setting? So, I told her to take four pics of the same thing at each of the four quality settings. They all four came back at 96 dpi? Shouldn't each quality setting give you different dpi results? Or is her camera just older? Or different? On my Kodak 4MP camera, my best setting gives me 230 dpi. My brother has a 4MP Kodak camera. His best quality setting gives him 230 dpi, also, but a larger length/width dimension than mine. Would someone be so kind as to explain to a new digital camera user how MegaPixels work, or are defined/manufactured? What dpi does a 6MP camera give one? Thanks, kindly for all replies. Much appreciated. TallPockets.


TallPockets ( ) posted Mon, 25 April 2005 at 9:51 AM

Oops! That should have said, "my brother has a '5' MP camera"! (my first mistake all year. WINK).


3DGuy ( ) posted Mon, 25 April 2005 at 11:03 AM

DPI and megapixels basically have nothing to do with each other. The amount of (mega)pixels refers to the resolution of the sensor of the camera. DPI (or dots per inch) only has relevance for calculating print size, meaning the number of dots (think pixels.. not quite but sufficient for now) printet per inch. For example. Say you want to print a picture 10x8 inch. If you want it printed at 300DPI you'll need a resolution of 3000x2400 pixels (or 7.2 megapixels). But if you want to print that same picture at 150 DPI you'll only need 1500x1200 pixels which translates to 1.8 megapixels. Or the other way around, say the camera gives you 6 megapixels (3000x2000 pixels). Now if you print this image at 300 DPI the image will measure (3000/300=10, 2000/300=6.7) 10x6.7 inch. Were you to print this image at 600 DPI, the resulting image will be (3000/600=5, 2000/600=3.3) 5x3.3 inch. Both images will have the same amount of detail though, the only thing that differs is the printed size. Hope this helps.

What is a friend? A single soul dwelling in two bodies. - Aristotle
-= Glass Eye Photography =- -= My Rendo Gallery =-


TallPockets ( ) posted Mon, 25 April 2005 at 11:40 AM

3DGuy: Thanks,kindly. I graduated third - in a class of two. Third grade was the hardest eight years of my life. WINK. You're going to have to 'dumb way down' for me. LOL. Ok, let me try it this way. I have a 4MP camera that takes 230dpi pics. My sister has a 4MP camera but it says her pics are taken at 96dpi. Are you telling me that both mine and her cameras will take the same 'quality' shots even though the dpi says much different numbers? My brother has a 5MP camera at 230 dpi but a slightly larger lxw. I know a person who sent me a pic from her digital camera that showed it was taken at 381dpi. If dpi doesn't matter for 'quality', why would someone spend tons more money on a 6MP camera versus a 4 or 3 MP camera? When I've viewed a few pics here from people that I know have a 6MP camera, they look much better than pics I see with only 3 or 4MP. Or are my old eyes deceiving me? LOL.(Remember, I'm not the brightest bulb in the room). Thanks for your patience. T.P.


TwoPynts ( ) posted Mon, 25 April 2005 at 12:39 PM

3Dguy layed it out pretty well. Basically, the dpi is not a measure of quality, just the amount of pixels a image fits into an inch. The more pixels per inch, the higher the print quality. 96dpi is standard PC screen resolution. A 4 megapixel image can be any dpi, but the print size will decrease as the dots (or pixels) per inch gets larger. An 8 MP camera will capture more data than a 3 or 4 MP one. Thus you can blow your images up larger, get finer detail, and print out larger quality images. The dpi is just a setting...not a final factor in quality. You can change the dpi within an image and it will still be a 4MP image, just either printing at a smaller or larger size. I hope that helps! --Kort

Kort Kramer - Kramer Kreations


danob ( ) posted Mon, 25 April 2005 at 1:45 PM

Some good answers but here is a link you may find helpful http://www.suite101.com/article.cfm/17310/102596

Danny O'Byrne  http://www.digitalartzone.co.uk/

"All the technique in the world doesn't compensate for the inability to notice" Eliott Erwitt


3DGuy ( ) posted Mon, 25 April 2005 at 2:40 PM

Both 4 megapixel camera's make pictures that have the same resolution (around 2460 x 1630) regardless of what the DPI setting is. The DPI setting of the camera is just an arbitrary value, in your case I'd ignore it all together.

What is a friend? A single soul dwelling in two bodies. - Aristotle
-= Glass Eye Photography =- -= My Rendo Gallery =-


TallPockets ( ) posted Mon, 25 April 2005 at 4:17 PM

Thanks, MUCH to ALL. T.P.


b2amphot ( ) posted Mon, 25 April 2005 at 9:18 PM

Yeah, thanks from me too, was curious about that myself.


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