Sonnar f/2.1 50-150mm Zoom Lens in Arri PL mount
Actually, I'm not sure that it is Zeiss lens. 'Sonnar' name seems to be engraved over some other name as you can see on the picture.
Thanks to the Konvas users group input, I'm quite sure that it is renamed and improved 35OPFP1-1 zoom lens made in very limited quantity by CKBK in 1980's. Great fast zoom lens. I had four of them so far, and all customers were satisfied.
The lens itself seems to be well made. Quite fast for such a zoom at T/2.3.
Improvements over original OPFP1-1:
Industry standard 32 pitch (mod 0.8) follow focus gears are installed over all three control rings (focus, zoom, aperture);
Arri PL mount (high-quality stainless steel) allows using this lens on wide range of old and modern film and digital cameras, including Arri, RED, Black Magic and many other (virtually any if your camera has PL mount or you have corresponding PL adapter);
Body is painted with anti-reflection black paint;
Diaphragm replaced to offer you full aperure range of T/2.3-11 instead of original f/2.2-4.
So, it seems that that CKBK was intended to market this lens in the Western world, and this was the reason why they improved and renamed this particular lens to something that look familiar to western user. Taking into account the serial number, there were 2-3 such modified lens made before production at LOMO was stopped due to USSR fall.
Optical condition is excellent - glass is clean and clear.
Mecanical condition is excellent - all rings rotate smoothly.
Don't miss your chance to get quite unique lens.