This is a 1940 CZJ 5cm F2 Sonnar in a 1962 J-8 focus mount. Shimmed to perform best wide-open and close-up, infinity is good stopped down a little. The lens on my Canon P Close-up and Wide-Open Focus is spot-on. Strong back-light, This lens was originally in a collapsible Contax mount, and the coating is in remarkably good condition. This is one of the first coated lens brought to market. The 5cm F2 Nikkor is very close in rendition to this lens, the Nikkor has slightly more contrast. I'll have to do a side-by-side comparison this Fall.