I just bought the Nikon D3S body and the was having focusing issues. Called Nikon support and explained my problems (outlined below) and they told me to return it to seller. I did. Received a second body a few days ago from a different vendor. Same problems!!! I even took the body to our best local camera shop to try out the Nikkor 70-200mm and not only did it have focusing issues, but the AF stopped working completely after firing off a few test shots! I had to reset the camera body to factory default and start over.
I went through Ken Rockwell's custom settings item by item and reset the camera a third time. I'm still having issues where focus isn't tack sharp, and when shooting on S mode (to control focal point) the camera keeps trying to focus on its own and fires off shots even when I haven't depressed the shutter.
I've been reading and reading forums all over and am finding all kinds of focusing issues with the D3S. I am thinking I need to stick with my D300s as this camera simply isn't performing correctly in MY hands, anyway.
So...in reading even more just now as a last ditch effort, I saw a comment about watching out for the AF-ON button on the vertical. I just picked up the camera as I would to shoot and I realize that the palm of my right hand has been depressing that button inadvertently!!!!!!!! That explains A LOT! I am a female shooter and I think maybe this body is too hefty for my hands because in order for me to have a good grip on the D3S my palm does often settle on the AF-ON button in the lower right corner of the back body.
The AF-ON Vertical button does not have an "off" feature...you can only customize it as to how you want it to work, so I think I am toast. At this point I am either going to have to retrain myself on how to grab and grip the camera body, or else send it back.
I'm very sad (and frustrated) because I do a lot of low light commercial shooting on the fly and the ISO range is what made me invest in the camera...if it worked as advertised (in my hands) then it SHOULD have been perfect for me.
