Nikon D810 autofocus at Dusk

[merv]

Was doing some landscape tripod photography last night with my new D810 approaching sunset, it was about 9.30pm and i noticed that the camera wouldn't autofocus when posting at a castle about 200metres away. Had to fiddle around and point the camera in a different direction to get it to work. When it eventually locked on I switched it to manual. Is this because the light levels were too low. Have just sold my D4 which never gave me this problem.
Comments please
merv

 

[chrism_scotland]

I suspect its due to light levels, I used to get similar problems with my D800, the AF just isn't rated to focus in as low light as some of the other Nikon bodies (D4 or even D750)

 

[f/1.2]

I have only had my D810 since yesterday morning but first impressions are it is better than my D800 in low light but not as good as my D4S or D750 which to be fair is what I expected.

 

[stemll]

I had a similar issue at Le Mans with my D5100. Eventually resorted to manual focus as it was getting annoying