I love experimenting new techniques, old cameras or equipments. My passion for old camera equipments started when I found an old Praktica in a second-hand market more than 10 years ago. The camera was rusty and nearly broken but my eyes were attracted by the lens.
Lenses with M42 mount were manufactured by many vendors (from Zenit, Zeiss to Praktica and many more) in late forties until early eighties. So it's very common to find such lenses in second-hand market for a cheap price (I even purchased some for 1 or 2 EUR).