The 20mm/2.8D AF lens is interesting, whether on 35mm film or on FX digital format. With it you can go out taking landscape shots without getting fish-eyed while still getting more or less the whole view at 94 degrees. You can also use it for "environmental portraits", having a humble object somewhere in the middle of the frame and all of the interesting surroundings too.
I don't have a whole batch of lenses, but I have some good ones. I consider the small 20mm AF Nikkor being one of the most useful. I use it a lot, both for landscape and when I want to have a compact combo on the shoulder.
Due to the construction of this lens, you achieve a total depth of field (DOF) at F22 - from your feet to the horizon. Some say that this lens is a tad sensitive - I guess the complex construction in a small, physical package is the reason.
The lens takes 62mm filters, which are definitely cheaper than the 77mm ones you need to use for its wider sister, the Nikkor AF 18mm/2.8D. The 18mm costs more than double compared to this lens, yet you don't have to be afraid that you're saving on image quality - you're not.
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