When an object becomes so valuable that one hesitates to use it for its intended purpose, then, in a practical sense, it becomes worthless. I think the Noctilux is there.. . it's acquired a cult status all out of proportion to its performance.
Dear Kevin,
I completely agree with the last point, about cult status, but looking at my favourite pictures shot with the Noctilux (attached), I'm half tempted to buy one just in the hope of getting more pics that I like as much. If I did much more photography of performing arts, I'd buy one like a shot.
It was always supposed to be a specialized lens, and it was always expensive new; the (formerly low) second-hand price reflected the fact that it really is an extremely specialized lens; and, of course, a much stronger dollar. At the $0.89 that a euro cost when Clinton left office, versus the $1.58+ it costs today, a $5,500 Noctilux falls to a bit under $3100: a price that any of us would be much happier to pay.
As well as the collapse of the dollar, the problem arose, I think, when more and more people bought it for reasons of what they perceived as prestige. There are, after all, plenty of photographers who (wisely) prefer to be judged on the price of their kit, or the on size of their front element, rather than on the quality of their pictures.
Is the Canon f/1.2 a poor performer? Well, you can't tell anything from pictures on the web, but of the two I've owned (one rebuilt by Optical Instruments Balham) and the others I've tried, I've never been impressed. Nor have any of my friends who own or owned them. This comes back to something I said elsewhere: when these lenses were a lot newer, they were also a lot less highly praised. I bought my first 50/1.2 almost 30 years ago, and so did some of my friends.
Over the years I've owned or used more than a dozen really fast lenses (f/1.5 or faster) apart from my Canons: 35/1.2 Nokton, 35/1.4 Summilux (pre-aspheric x2 -- one was stolen -- and aspheric), 50/1 Noctilux, 50/1.2 Nikkor, 50/1.5 Xenon, 50/1.5 Summarit, 50/1.5 Nokton (both old and new versions), 50/1.5 Sonnar, 55/1.4 Pentax, 58/1.4 Nikkor. I think I'd choose any of them except the Xenon, Summarit and (maybe) original Nokton over the Canon for use at full aperture unless I wanted low contrast and sharpness. I'd certainly sacrifice half a stop to use the f/1.4 and f/1.5 lenses instead.
EDIT: I should add that I fully accept that it is possible to make good pics with a Canon 50/1.2, or indeed any other lens,
with the right subject and technique. That is true of any lens. I've just never found that the Canon suits a wide range of subjects -- nor that it is as good for those subjects as some of the other lenses I've had.
Cheers,
Roger