I recently purchased a 180mm lens along with a Rapid Omega 100 body and 2 other lenses (I now have 2 Rapid Omega 100 bodies). I seem to be having a couple of problems with the 180mm lens:
a) The focusing is way off. I've taped scotch tape to the film plane of the camera body (after taking off the film back & the camera's top plate) to see if what the rangefinder says is focused is really in focus. Turns out, it's not. The rangefinder focusing is way out of alignment. Subjects that are 12 ft away will only be in focus in the film plane when I use the distance scale on the focusing knob (i.e I set the knob at 12ft for the 180mm, and checking the scotch tape GG, I see that the subject is in focus). Using the rangefinder patch in the viewfinder, the same subject is definitely not in focus on the film plane when the patch says it is. But, the funny thing is that the rangefinder focusing with my other lenses (58mm and 90mm) are spot on on the same body, and my checking with the scotch tape on the film plane confirms this. I've also tried using the 180mm on my other Rapid Omega body but the results are the same.
b) The gridlines in the viewfinder for the 180mm is visible when the lens is focused at infinity, but when I focus at closer stuff the gridlines for the 180mm lens just disappears from view in the viewfinder. Also, when I look through my 'scotch tape ground glass', the view that I get with the 180mm lens doesn't change at all when I focus the lens at closer subjects. Isn't the view supposed to change/shift to compensate for parallax?