I appreciate your comments, but I think we are getting away from the point.
The main message I want to get over is that to show that a rare item such as the "Fed-Stereo" lens ever existed and was available to buy there must have been something written about it somewhere in the press. I can't imagine an item like this going on sale and nothing ever being written about it in any book or journal.
The same goes for the so called "Fed-Sport". Photography was very popular among Soviet people, and the introduction of something like the "Fed-Stereo" lens would have caused a sensation at the time.
So what I'm saying is that if an article about a certain photographic item was never written and doesn't exist, then in all probability neither does the photographic item in question.
You say that all known fakes never had passports, or any other documentation. I don't know if this is true or not, but if the fake and the passport were done well enough, they would pass for genuine and no one would be ever be any wiser.
I have high respect for what you say and the depth of your knowledge, and the same goes for Bill, but I believe that both your good self and Bill are mistaken when you say that the documentaion for a camera or lens would be too difficult to fake.
I'm not qualified to say for sure, but my instincts tell me that these documents would be relatively easy for a skilled forger to produce.
Bill says, Quote: "It may be easy to fake new paper objects, but to make them look old is difficult". I don't agree, a good forger would probably just use old paper! There are plenty of sixty and seventy year old books for sale everywhere.
And the forger doesn't even need to copy anything. The item being faked never existed, and neither did the pasport, he can invent a new one as long as it is in keeping with the general style of the manufacturer. Make no mistake, from what I have seen recently these people can be very clever, skilful, and cunning,"хитрый" (Heedri).
But I too digress and am drifting away from my main point, and that is that for items such as these they would surely have been well documented at the time they were on sale, and if that documentation doesn't exist then in all probability neither did the item.
Best wishes to all, but especially to Zoom and to Bill