What do you considering the upper limit for ISO?

RichA wrote:
Lets say you aren't pretending, like so many do that you can take
really good images at high ISO. Where do you draw the line? Canon
and Nikon are now boasting 100,000+ ISOs for their latest offerings,
the Canon isn't even FF! But lets say you shoot with a D700 and you
have the luxury of going with either 3200 or 6400 ISO. Can you
produce a shot worthy of keeping at 6400 ISO? Or are we just kidding
ourselves that the output at that ISO, or from any camera is
acceptable?

The noise free upper limit (where reducing the ISO does not
sigificantly reduce image noise) varies with the camera.

For a D2x that was perhaps ISO 400.

For a D300 that is (as you state below) about ISO 800.

The D3 and D700 are essentially noise free up to 1600.

Perhaps the new D3s is noise free up to ISO 3200.

We can assume that in a year or two Nikon will introduce
a D4 that will be noise free up to at least ISO 6400!

I shoot a D300. IMO, beyond 800 ISO I have trouble accepting the
images as really good. I'm talking about non-noise reduced raw
images. Sometimes, it's possible to use NR and not make the picture
look like crap, but the leeway is narrow.

Well, you can't do that anymore! I have a D2x, and I
have always had trouble accepting that images beyond ISO
400 are acceptable. Therefore, by your logic, you can't
do what you are doing! :-)
2
The fact is though, I also use a D3, and the upper limit
for it is ISO 1600 to be noise free (and I commonly use
it at ISO 4000 when some noise is acceptable).

I just don't see why you or a D300 limits other
photographers or cameras.

--
Floyd L. Davidson http://www.apaflo.com/floyd_davidson
Ukpeagvik (Barrow, Alaska)