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Red Robin

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Brian , You wrote that my helical may be 180 degrees out. By following the directions in the two posts will I have to collimate everything with the kind of equipment that you write about, or just turn it to the right place and it should work. Also you state it is a transition lens, will it need a complete readjustment for western cameras?
 
Most of the transition lenses that i have seen worked well enough with a Leica- although some benefitted from some adjustments. Those were off to begin with. It is not hard to do. Shims can be cut from aluminum foil, or even paper. The worst is realigning the aperture ring.

With the helical being out of phase by 180 degrees: the helical unscrews from the mount- 1 set screw; the focus ring comes off of the outer helical- three set screws and the "extra", longer screw that acts as the close/far stop. I always scribe the position that the inner and outer helical make before taking out the guide screws that keep them together so i can reassemble. In your case- sounds like marking it will help reverse it. Undo the guide screws, this allows the inner helical to come out. The outer helical has a rotating ring that drives the action to focus the lens. Make sure to keep it at infinity to allow correct reassembly. There are many starting positions to get the helical back in, two will result in correct focus, but only one will give correct focus and align the aperture index. Took me a while to figure that one out.

SO: when the helical is correct, with the outer ring set for infinity, the holes for the guide pins will be near the bottom of the slot.
 
Brian Sweeney said:
Most of the transition lenses that i have seen worked well enough with a Leica- although some benefitted from some adjustments. Those were off to begin with. It is not hard to do. Shims can be cut from aluminum foil, or even paper. The worst is realigning the aperture ring.

With the helical being out of phase by 180 degrees: the helical unscrews from the mount- 1 set screw; the focus ring comes off of the outer helical- three set screws and the "extra", longer screw that acts as the close/far stop. I always scribe the position that the inner and outer helical make before taking out the guide screws that keep them together so i can reassemble. In your case- sounds like marking it will help reverse it. Undo the guide screws, this allows the inner helical to come out. The outer helical has a rotating ring that drives the action to focus the lens. Make sure to keep it at infinity to allow correct reassembly. There are many starting positions to get the helical back in, two will result in correct focus, but only one will give correct focus and align the aperture index. Took me a while to figure that one out.

SO: when the helical is correct, with the outer ring set for infinity, the holes for the guide pins will be near the bottom of the slot.
Click to expand...

How thick/thin does the shim need to be overall, or is each lens different?
 
Each lens is different, and exact focus requires that the total thickness of the shim be within 0.02mm.

Your best bet, reassemble the lens and try it out with something easy to determine correct focus, like a ruler. Some trial and error is involved, but instructions for setting/checking the focus are here:

http://pentax-manuals.com/repairs.htm

If the lens focuses behind the subject, thicken the shim. If it front-focuses, reduce the shim.
 
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