I'm giving up on buying a 21mm f2. The prices are outrageous.
There weren't that many made. The price is what a buyer is willing to pay.
You don't need the 21/2, the 21/3.5 is an outstanding lens. I much prefer it to the Nikkor 20/2.8 AIS, which is the other wide angle that I shoot with.
Like getting apartments in NYC, you have to hit the sidewalk and visit the dealers, small shops, estates, etc. It really becomes a quest for something rare. Still, wide is wide, and 21/3.5 is good. It depends on what you're shooting, too. There are always photographer/collectors... All you need is one camera and one lens in the right time and place.
Unfortunately, you're battling the digi's that want these lenses for their small format electronic cameras.
On film, I rarely even use my 24/2.8 since it is just on the edge of too wide for me. I can't really imagine needing a 21mm. I probably would not use it more than two or three times a year.
But I sure would love to catch a 28/2.0 someday.
I realize this thread is some old, but i just got the 18mm. It's so good! All though i think its the same asking price, if not expensiver than the 21mm, i got it for free, and i enjoy it a lot allready.
You are a very lucky person. I'm still looking for one.