Definately a keeper, in my opinion. While not near as fast as the 3.5cm/1.8 Nikkor, the Biogon produces great images. I much prefer the post-WW2 Carl Zeiss/Zeiss-Opton version over the pre-war CZJ because I think that the post-war lens is sharper, and has better color rendition. Be advised that some folks are of the opinion that Zeiss wrecked the lens in the post-war re-design.