Thinking of buying a Nikon D800? Be careful when you use it! I have covered the often overlooked danger of [URL="http://dpnow.com/7644.html"]diffraction limiting[/URL] before. If you reduce the aperture setting in your lens beyond a certain point that relates to the pixel pitch of your camera's sensor and your images will get softer because of diffraction.

It struck me that with such a huge leap in pixel density between the Nikon D700 and the new [URL="http://dpnow.com/8519.html"]D800[/URL] that photographers upgrading to a D800 will have to modify their use of apertures in order to benefit fully from the extra resolution afforded by the camera.

If you use a D700 you can use apertures as small as f/16 before diffraction starts to make a visible difference. The 12 megapixel full frame sensor on a D700 means the pixel pitch is a whopping 8.5�m. compared to 4.9�m with the D800. The diffraction threshold for the D800 is only around f/9. With 22 or 24 megapixel full frame DSLRs like the Canon EOS-5D Mark II and the Sony Alpha 900 the threshold is around f/11.

So, if you're buying a D800 because you want every ounce of detail those 36 megapixels offer, be careful with your apertures! I notice that in the Nikon D800 brochure some of example images are labelled with settings beyond the diffraction limit...