I used to be a Leicaholic (Barnack cameras and M-3s only - none of this new stuff for me). My father-in-law recently gave me his hardly used Exakta 500 (really an Exa) bought new in the '60s and I was surprised at the tactile appeal and the excellent quality of its 50/2.8 Tessar, although the focusing screen is really terrible, in my opinion. I had always shunned Eastern bloc photo equipment. Now I am infected with the Exaktavirus and I've gone out and acquired a Varex IIb and a 58/2 Biotar in good working order for ridiculously low prices. This quirky camera has me really in a fever and I find myself scouring auction sites and classifieds for bargain priced lenses. Right now I've developed a pathological desire to acquire a 35/2.8 Flektogon, the one that is referred to as a "Macro" lens, focusing down to 0.18 meter (7 inches or so ). Anyone have any opinions on this lens? I'm bewildered by the variations of East German Zeiss lenses that are out there. Aside from the different descriptors found around the lens bezel, there are lenses with seven digit serial numbers and four (!) digit serial numbers. What gives here? Lenses with six blade, eight blade, ten blade, twelve blade iris. I'm sure that many re-designs occurred over the years as well as concessions to economic conditions. I've heard that quality declined as the 60s and 70s wore on. Is this true? How does one make an intelligent decision short of testing every potential purchase? Which lenses or production era is to be avoided? Is there any sort of general consensus regarding the peak period of consistent highest quality production?