Quote Originally Posted by jnanian View Post
only a few years ago a brass lens was considered JUNK and cost maybe 30$
the same lens now costs between 600 and 800$

the reason that polaroid back is $$ is for the same reason ... someone will pay that much money for it
That's pretty much it, if noone paid it, the prices would drop. I've heard of people getting 50/1.4 Taks for $10, and Helios 85/1.5 for $100 ten years ago, now you're lucky to get one under $100 or $400 respectively.

I also want a Polaroid 405 Back (or Fuji PA-1 or 145, or whatever takes FP3000C), but I'm just not going to buy until I see one under $100. I expect I'll be waiting a long long time.
It's also just the fact that FP3000/100 is the only size readily available. 4x5 Instant is gone, you can get a 4x5 holder for $10 (I got one to use with Quickloads). Maybe if Impossible release a 4x5 film those holders will go back up to $100-200, and 405s will go back to $50...

There's also the economic rule of "expectations of inflation cause inflation", in that if I think I can buy/sell a lens for $200 in a few years, and it's only $100 now, I'll buy now and either save/make money on the future price. That's how property/stockmarket/tulip bubbles form. Maybe we're in a lens bubble, and the prices will crash in a few years?