Attached Link: http://www.renderosity.com/messages.ez?Form.ShowMessage=1740708

While you can load an 16 bit tiff, my experience suggests that the output of the image node is still only 8 bit. It gets more noticeable on higher displacement values. I got the same effect from 16 bit Tiffs as from the same map reduced to 8 bit in Photoshop. With the method in the link I got better results.