There are many excellent Eastern Europe lenses of the past with the M42 screw mount, and I have some, e.g. the Helios 44M4 58mm f/2. Built in the former Soviet Union to equip Zenit cameras. The latter, while if robust, often have limits, both operational, and reliability. To play it safe and always staying behind the Iron Curtain, should turn to production in the former GDR. Still were German! And so, I did not miss a couple of Praktica Mtl5 bodies . One normal, and the other in B version. These differ between them practically only in the power source of the TTL CdS meter. The second in fact, uses the current LR44/SR44 batteries, while the first was designed for use with the PX625 mercury.