Nikon today issued the expected 2.10 firmware update, which fixes a number of issues, improves autofocus, as well as adds one capability.
The new capability is to assign a button (CSM #F2) to correct electronic shutter timing to frequency based lighting. This function is only available in Shutter priority or Manual exposure mode, but allows you to set non-standard shutter speeds that are synced better with the lighting frequency. This function works between 1/30 and 1/8000 second and tunes in 0.0104EV steps (1/96EV). Note that you have to verify reduction via examining the resulting photo, not the viewfinder, as the viewfinder is running at a frequency that is fixed.
Autofocus performance has been improved in two primary ways: (1) subject detection now does a better job tracking small subjects. I note it also seems to improve face/eye detect on small subjects, as well; and (2) does a better job of rejecting bright/contrasty background detail in most of the AF-area modes, meaning that the subject is now more often found and focused on in such situations.
In terms of the fixes, there were many, including three that I had reported. The big one that many users ran into is that when you select Focus for CSM #A1, the camera would disable the shutter release with some lenses. This is now fixed. But so, too, are a number of other more subtle issues, including one that didn't allow you to always correctly recall Subject Detection via a customized button. It's possible that some even more subtle things were addressed, as well, but when things get truly arcane, Nikon generally doesn't document those changes in the notes, though they'll sometimes contact the person reporting the issue that was fixed to tell them it was addressed.
Overall, this is another of those "you absolutely should install it" firmware updates.
The update is available, as usual, at Nikon's download center.
