Nikon D7000's ISO levels

With the Nikon D7000, I rarely shoot at higher than ISO 800, but there are the odd times when you just need to push the limits of the camera.  I was in Ottawa this past weekend and ISO 1600 and ISO 3200 was the norm at night.  There was only one place I visited at night--Parliament Hill.  If I could, I would have visited Occupy Ottawa, I was told just east of Parliament Hill.

I did bring my tripod but the night I used it, it was so cold so I did not spend much time on the Hill.  The second night was warmer and was cloudy--great for photography by the way--but I forgot the bring the tripod along so it was all hand-held.  I also had my not-so-fast 18-200mm walkaround lens on.  With a not so great setup, I had to resort to pulling as much juice from the D7000 as possible.

So, hand held, these were some of the pictures I took with the D7000:

50mm, ISO 3200, f/4.8, 1/15 seconds:

18mm, ISO 1600, f/4.0, 1/6 seconds:

18mm, ISO 1600, f/4.5, 1/5 seconds:

18mm, ISO 1600, f/4.5, 1/4 seconds: