Great ultra-wide prime lens.
Small size, great performance (sharpness/contrast), fast AF, rugged build.
Price. It isn't free. It won't make you coffee.
I have two of these now, as my wife and i can't share it. This is my favorite Nikkor lens, and i use it all the time. Very rugged, very sharp, very easy to take great pictures with. Just watch out for the rear element, they often get scratched/banged up.
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