Focus at infinity

OpenWater · 03-23-2006

I've got a question about the focus of my IIIf with a 50mm Elmar that some of you may be able to answer. I just received the camera back from a CLA. It looks wonderful and sounds great. I'm very pleased in general. Nonetheless, I noticed that when I rotate the lens to lock at infinity it is not quite focused in the rangefinder. By pushing it back a little bit (enough to see on the lens scale in front) it snaps into focus in the rangefinder window. Is this normal or should I contact the repairer and ask him/her to readjust it?

OldNick · 03-23-2006

What distance away is the object on which you focused with the rangefinder? It should be several hundred yards, a mile if possible. You might try focusing on the moon. If it is still out of agreement with the lens scale, I would seek an adjustment, because it would likely be in error at all distances.
Jim N.

doubs43 · 03-23-2006

In addition to OldNick's advice, I'd also try more than that one lens on the body. I have two pre-war 50mm Elmars and neither one has perfect coincidence at infinity while my other lenses do. One is close enough for DOF to cover the error while the other has been relegated to copy duty. Both being pre-1933, I'm thinking that the one that's off the most may have been dedicated to a specific body and not intended to interchange with other cameras. The other is close enough to be an interchangeable model. There are no adjustment provisions on the Elmar to correct for infinity.

Walker

OpenWater · 03-23-2006

Thanks to both of you for your comments. OldNick is right; there is infinity and then there is infinity. (Shades of Sam Jaffe on Ben Casey - my age is showing...)

I am in a six-story building and was playing with the camera through my window. Things across the street (100 meters or so) were giving me the problem. After your comments I opened another window and focused on buildings more than two kilometers distant. The images are crisp; everthing must be fine. I'll try the moon tonight.