This week I bought a D90 and a Nikon 18-200 lens. Together they weigh about 1200g. My old camera and lens weigh about 700g. That means that I am now holding an extra 500g.
I took the camera out yesterday to my son's soccer game and took some photos, most of which at 200. None of these photos were sharp. I played a bit with shutter / appeture controls but could not achieve a crisp photo. Later at home I tried again to hand hold the camera and then take the same photo on a tripod. The tripod ones were sharp and the hand held ones not in focus. So I am deducting that I have a fair amount of camera shake when I am hand-holding the camera.
What I am interested to know is if anybody else has had this problem after upgrading to a heavier camera/lens and if this is something that resolves itself over time with practice.