Probably how you imported them into software. The files themselves don't really have a ppi - they're just pixels. They don't have a pixels-per-inch until you put them on some medium. So if you print them, a ppi is useful. But until they, ppi is just a number.
_____ Brian... a bicoastal Nikonian and Team Member
My gallery is online. Comments and critique welcomed any time!
>Are the some of the image being cropped and others are not? > >If so then check the settings of the crop tool. >Photoshop allows you to crop to a certain size (in inches) and >resolution (in ppi.) > >Other then that I can not think of any reason that Photoshop >is treating these files differently.
No cropping at all. All images are 100% as they came out of the camera then into ACR for minor adjustment then to CS3.
I don't know why ACR is downsampling the file but there is a simple fix, use ViewNX to convert to tiff, then import into CS3. It's an extra step but you'll get the full raw data out of the NEF that way. Or use NX2.