It's not to do with the iso performance, but the DR. Its only at its best between 100-400iso over this and the dr drops. .
What is the recent obsession with dynamic range? There are many threads like this, on many forums when discussing the D800 for some reason. It rarely seems to happen with other cameras. I have this feeling that there are D800 owners out there who only shoot at ISO100, at f5.6, on a tripod, with a remote release and mirror lock up. It's ridiculous Just use the damned thing as a camera instead of some delicate scientific measuring tool.
It's nice to know you've got 14 stops of dynamic range if you want it, and yes, it's something worth considering when deciding what camera to buy, and sometimes, it has actually been useful to me, but to suggest that once you start to use smaller apertures or higher ISOs it suddenly changes into this decidedly average camera is patently ridiculous.
"Oh no... I need ISO800.... my dynamic range will only be the same as other mere mortal cameras now.. I can't possibly take the shot!... the shame of it!!... I'd rather miss the shot of the alien ship beaming up 10 Downing Street"
Seriously... is this how we measure what makes a great camera these days? The D800 is only great at ISO200 and at f5.6? Whatever limitations higher ISO place upon the camera, other cameras
also suffer the same issues diminishing returns if you plot DR against ISO. You've still got around 1 stop of DR over the 5D MkIII at 12800... so what? If you're worrying about DR at ISO12800 then you're really missing the point of what photography is about if you ask me.
There's no practical difference between ISO100, 200 or 400. Apparently.. your DR will drop from 14 to 13 stops ... well big fat so what? You'll never actually see the difference between images shot at 100, 200 and 400 even if you print at A2 so far as noise is concerned (and that's what actually matters) unless you are shooting in outrageously contrasty conditions. At ISO800 you're pretty much in the same league as a 5D MkIII ... which is terrible or something? LOL
I disagree that it's "very, very easy" to see this drop off at all. It's very, very easy to see it on a chart... but in reality?
Reading this thread you'd be forgiven for thinking the D800 is only worth buying if you shoot below ISO200 on a tripod at f5.6... and if you don't, you may as well buy anything else as there's no advantage in owning one.
You don't get these discussion about the D610, which has almost identical DR characteristics as the D800... in fact, at the very top end, out-performs the D800.