The contax ii is a solid machine I have a bad habit of covering the rangefinder window with that model. Using the contax model I is a little time consuming mine was made in 1933 I think the rangefinder base is slightly smaller in the model one at least I don't cover the rangefinder window with my finger. I have't used russian lenes with it yet. I bought my contax iia at an estate sale I've gotton a older heavy brass chrome nikkor 35mm f2.5 and 135mm nikkor made for the contax with the camera these work nice. Although I read the wide angle nikkors are made only for the nikon but depth of field is great enough not to notice the focus difference. I wonder what other lens brands are made for the contax?