Hi everyone,
Will the nik filter work as well as the tiffen filter?

I have solved the problem. The NEF file needs to be converted to a DNG file.You can download the free DNG Converter application, then when you shoot your NEFs you can convert them to DNG format, which Photoshop CS4 will open with Camera Raw. You also need to go to the Adobe site and get a plug in for the Photoshop, which depends on your camera make and model. You need to follow the steps and choose the right one. Mine for the D7000 is 6.3

Thanks John for responding. I love Photoshop and use it all the time. I just got a nikon D7000 and want to learn how to use raw images and now I find out that Photoshop does not accept NEF.

Apparently Nikon's NEF raw format is not compatible with Photoshop. How can I convert a NEF raw image into a format that Photoshop will recognize and accept.