Nikon D810 - power aperture not working while recording

<p>Hi<br /> Using the power aperture function on my D810 works fine as long as I'm not recording. As soon as I start recording the aperture stays locked and the Fn/Preview buttons do nothing - in other words, the power aperture function is not available.</p>

<p>I'm trying using Manual mode (and I've tried it in A mode also). I've tried with various lenses and I have no photo shooting info displayed.</p>

<p>Google searches for the same issue show nothing.</p>

<p>I'm absolutely at a loss to discover the cause of the problem.</p>

<p>I'm on the later firmware and I didn't try this before I upgraded the firmware. Therefore I don't know whether this issue existed on my camera with the original firmware or whether it's the firmware upgrade that's caused it.</p>

<p>Has anyone else experienced this?</p>