I went out this afternoon with my D7100 with the older version of this 300mm f/4 lens on it. I shot it handheld wide open. It was a cloudy/snowy day.
Anyway, I shot the below photo of a McDonalds sign at their street entrance. I suppose that I was about 30 yards away.
The first photo is the entire image. The second photo is at 100%.
You can see that this lens has incredible sharpness, even wide open hand held.
This lens is handholdable if you remove it's tripod collar. Also it's fairly economical (I recently purchased one for a little over $600 USD).
For those, like me, who like Nikon photography and are on a budget, the AFS 300mm f/4 Nikkor (older version) is a great telephoto option to consider.
Also, here's a link (
http://www.lenscore.org/ ) to "LenScore's" Nikon Prime lens rating page. They rated the older AFS 300mm f/4 version of this lens that I have 8th. That's very high, especially when you consider the seven lenses that are rated above it are all much more expensive. Please note that the newer version of this lens is only rated 16th.