Pixel Rating vs. Resolution (CoolPix 4300)

People,

First of all . . . I'm new to the group; & wanted to say hello to

everyone.

Now, my question.

I purchased my digital camera (CoolPix 4300) before I really knew

anything about industry standards or so many technical aspects. It

now occurs to me that . . . well, let me put it this way:

What's the sense in continuing on with the Pixel Rating wars, if the

resolution remains at 72 ppi for most of these cameras (in the

industry)? What is the advantage of grabbing a 4 or 5 megapixel

camera, if the top resolution for a .jpg remains at 72 ppi? The

result of a high Pixel Rating & a low resolution is just simply a

huge photo, dimensionally! Right?

The quality of a digital photo is accomplished by higher resolution,

right?

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OK, enough on the philosophical side . . . maybe someone can help me

on the technical side:

Is there any way (on the 4300) to change the .jpg resolution to a

higher setting than 72 ppi. Is there something I missed in the

manual, or on the controls?

Thanks much,

mark4man

BTW - I know the camera has the ability to shoot 300 ppi .tiff's. I

was just hoping there was some moderate ground on the .jpg's, to

increase photo quality (resolution) & thereby decrease dimensions.

The resolution you state at 72ppi does not matter. Nikon chooses that for jpg because on older monitors the resolution was about 72ppi (my LCD screen is 150ppi, so its really a stupid number to rely on anyway). Nikon chooses 300ppi for the tiff because for printing output at high quality thats a standard way to "rez" (or res) your file.

All you really worry about is the overall dimension of your file, which is those two big numbers in pixels defining the whole frame. (an arbitrary example is 2450x1930, which is by no means close to anything correct). With that big number you can divide by 72, or by 300 and find the size of how it may appear depending on what you're looking at it on or with.

Ultimately if you're planning to print you can adjust it to 300ppi in photoshop and Photoshop will automatically scale the dimensions to match so no data is created. You can do the same to adjust it to 72ppi, 100 or 150 although generally that doesn't matter because it will appear as different sizes on different screens. When I prepare an image for web I usually pick a maximum dimension for the longest side of maybe 600 or 650 pixels for example. The ppi doesn't matter.

Carl,

Oh man . . .

Thanks for the response (& you certainly know where you're going . . . moreso than I do.)

I guess now I'll have to wrap my head around what actually happens relative to the Image Size dialog in Photoshop, when the Resample Image box is checked vs. unchecked (& . . . I guess I've ruined every photo I've resized in the past year, due to the fact that that box has *never* been unchecked.)

Just a couple of final questions:

So that 72 ppi that I see displayed as the image resolution in Photoshop when I open up one of my Nikon photos . . . based on what you're telling me, is that a function of the camera itself or the default image res setting in Photoshop?

In keeping with that thought, if I were to go with a smaller image size setting in the Nikon . . . based on this inverse proportion theory, would that increase the ppi for the shots?

Thanks again,

mark4man

Mark, set your Nikon for the resolution you want to capture, based on the largest size you'll either want to print (div by 300 for print inches) or view on the web (div by 72 or 96 for monitor display inches).

Cameras don't think in terms of ppi, since the number of inches is only relevant to output or destination. When you capture, it's simply pixels.

In Photoshop, make sure you change the 72ppi to 300ppi before you print to get "photo-quality" output.

Photoshop opens up any image at the 72 ppi by default, which is based on the conventional monitor resolution. The 72ppi has really nothing at all to do with the captured image. The capture resolution of your camera ( I'm not familiar with that model) lets assume is 4 megapixel, and for the sake of easy math, assume that it captures an image at H 2,000 x V 2,000 = 4,000,000 pixels.

Photoshop will open that image up as 27.778 inches x 27.778 inches print size at 72ppi. If you edit the 72 dpi and change it to 300 dpi, which is usually recommended for printer output, it will change the pixel count from 2000x2000 to 8333x8333 pixels. The print size of 27.7 x27.7 inches stays the same. If you would rather print a 8x10 instead, replace the 27.778 values by 8 inches and 10 inches respectively and see that your pixel count has been recalculated as 2400 x 3000 pixels.

Your original image is still a 4 megapixel capture, but PS plays with the output depending on what you are trying to do.

Hope this helps

Chris & Wally,

Thanks very much. In keeping with your instructions . . . I was about to begin a photo album project today; & was intending to open my digital photos first; to change the res to 300 ppi "without Resampling" (Photoshop 6.)

Will this matter at all?

& . . . should I Resample or not? (for color printer output.)

My original thinking was: Since my printer's res is 600 dpi, I wanted the digital photos to be 300 ppi. And since Photoshop can change the Pixel Dimension/Image Resolution realtionship without Resampling, I thought that would be ideal. Now, I'm not so sure.

Thanks,

mark4man

Mark

Try printing at 300 dpi without resampling if your camera has the pixel count. If not, then resample and you probably wont see a difference unless you really want to print large.

This is where the actual camera pixels make the difference. The larger you want to print, the more "out of the camera" pixels you need to maintain the 300dpi information density required. If you dont have "real" pixels to begin with, then PS will create the additional pixels it needs to print the image at the higher resolution / print size you need via interpolation. The interpolation that PS uses is not bad if you are only going a little bit larger, but you will see a difference if you decide to crop and then resize the cropped image larger. PS will have to create the extra pixels:

As an example: to print a 8x10 picture at 300dpi you need (8x300)x(10x300)=7,200,000 pixels or a 7mp camera.

To print the same 8x10 picture using a 4mp camera, PS has to create the extra 3200000 pixels. It does a pretty good job, though, and I recommend trying it. Just remember to save the edited/resized files under a new filename, keeping you original intact.

I have an Olympus E10 , 4mp camera that gives me great 8x10 at 300dpi, even after minor cropping. I have found though, that it is best to frame your image as tightly as you can to keep cropping to a minimum.