When this deployment is over I'm going to upgrade my camera. I'll keep the D3 for sports/SCA battles/kids running around; it will be more than enough "utility camera" for years to come. And I'm happy enough with the D700 IR convert for now, (lets face it, that's pretty much a luxury as it stands.) But I want to upgrade to an 800 series for fine art, portraits, and backpacking/starscapes. The thing is, I'm not sure if I should go with the 800E and upgrade my 85mm prime or get the new 810.
The biggest question is for low light portraits/events would I be better off with an 800E and an 85mm 1.4D or an 810 with my current 85mm 1.8D (picking that stop back up with the expanded ISO of the 810)?
Bear in mind, low light portraits/events only accounts for about a 1/3rd of what I would shoot with it and about half of that would be with other lenses, but that's the part that I'm trying to improve on right now as well the biggest part of how I bring in donations for the Wounded EOD Warrior Foundation.
My rule of thumb has always been going with the better glass when I'm in a spending quandary; but the upgrade in lens I'm looking at has a pretty specific and limited benefit, while the 810 has enough real ISO improvement (on both ends) and autofocus improvements to make me reconsider that policy.