Ali,

I bought mine for 20 pounds 3 weeks ago. Search Google as 517/16 and photographs would drop your jaw , I prefer it 30 times more expensive Tessar version. Its from 1954 or so. Have an triplet air spaced. It is razor sharp. Triplet have many interesting aspects , MTF suggests it sees the smallest and biggest objects at similar sharpness. Its rare at lens world.

Umut