I am a portrait and wedding photographer and have several Pentax cameras and lenses. I now have a 24inch iMac and now that I see larger images, I have noticed that my pics are not as great as I thought they were. When I zoom in 1:1 or 2:1 in Lightroom the faces always look blurry and the eyes are not sharp. I have a few question for the Nikon people here. 1. When you zoom in on a picture in Lightroom or Photoshop to 100 or 200% how sharp and focused are your pictures? Can you provide examples? 2. Any Pentax users convert to Nikon, if so, why and what are your results? 3. I'm thinking about buying a Nikon but don't know which to purchase. I'm looking at the D90, D300, or the D700. The D700 is a big price jump, is there as big as jump in image quality? 4. If I make the leap to Nikon, I will also want a backup body. Will a D5000 work as a backup and will the lenses work on all bodies? Thanks.