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Nikon D3s autofocus problem

This is the second time recently that I’ve had problems with my D3s and a 400mm acquiring focus in high contrast lighting (very bright sunshine) in hot weather (above 30 degrees C). This only occurs in this lighting, no AF problems in other conditions. This is similar conditions Rob Galbraith identified with the Canon 1D Mk III AF 2 years ago and again with the 1D Mk IV. You can see he’s also found similar problems with the Nikon D3s which he’s trying to track down.
You can see from the examples below that the red square of the AF point is locked on to a player but when you look at the 100% crop on the left its out of focus in the first 4 frames. The 5th frame is an example when it’s focused properly.
The current hypothesis is that its related to the brightness/contrast and temperature. More testing to come.
D3S - 400mm AF - sunny - high contrast
UPDATE 1: This is an email exchange I had with Rob Galbraith where he has also had similar problems:

Hi Syd,
Thanks for the message about this.
I have the same combo of gear, as well as the D3/D700 before, and have experienced an ongoing problem: in bright sunlight the camera appears to frontfocus slightly, whereas from the same distance in not bright sunlight (ie same soccer field but at night under the lights) it’s getting the focus distance exactly right. I don’t know if this is restricted to the 400mm or if it’s just the shallowness of the depth of field with this lens reveals the problem more than a lens like a 70-200.
We might be experiencing something that is related. I’ve had all my gear focus calibrated by Nikon now, twice, and so my next step is to see if I can get the attention of Nikon a little higher up. I’d welcome the the opportunity to discuss this with you further in the future.

UPDATE 2: I’ve encountered similar, and sometimes worse, issues with the Nikon D4. I gave up and have switched to use the Canon 1D X & C, and have been very happy. No such problems with the Canon.