Carenar 35mm focus trouble

dallypost · Joined: 07 Jan 2015 Posts: 8 Location: Rockland, Idaho

I use old Nikkor manual focus lenses to shoot micro four thirds video. Recently I was given a 55mm 1.7 and a 35mm 2.8 Carenar screw mount lens. The 35mm filled a hole in my lens collection so I bought an M42 to Micro Four Thirds adapter. The 55mm works fine on the adapter. The 35mm has problems. The closest focus is at about 4 feet instead of the two feet shown on the focus ring. On the other end, it focuses way past infinity. If I loosen the lens and screw it out about 2mm it seems to work as it should. I suspect that either the focus ring has been tightened down out of position or that the lens has been disassembled and improperly re-threaded on the helical.

I pulled the focus rubber off and found three equally spaced screws around the barrel of the ring. There is a forth and larger screw near the back (camera side) edge of the focus ring.

I also had another thought. I have never used screw mount lenses before. Are there cases where a shim is required between the lens and body to achieve proper function.

What are your thoughts regarding repair or other possible solutions? I don't want to tear into this lens until I hear a few ideas. Thanks all.

casualcollector · Posted: Wed Jan 07, 2015 6:19 pm Post subject:

The focus ring may have slipped then been tightened in the wrong position. The three small screws may clamp the focus ring to the helical. Another scheme has the clamp screws concealed by the name ring. Unscrew that from the front barrel and look for screws that would clamp the grip to the helical.

Is the lens marked Japan or Korea. I have and example of the Korean Carenar and may be able to help you.

dallypost · Joined: 07 Jan 2015 Posts: 8 Location: Rockland, Idaho

casualcollector, Thanks for the reply.

This is the Korean version. I did try to unscrew the front of the lens and it absolutely will not move. Because this has the three screws under the focus rubber, I think that this is how it is attached. I will try to loosen these and see if I can correct the problem. There is a single larger screw under the rubber and right next to the back edge of the focus ring barrel. Do you by chance know whit this is for?

casualcollector · Posted: Fri Jan 09, 2015 7:32 am Post subject:

The large screw may be the helicoid travel limiter. Best not to remove it at this stage. I'll try to have more info for you soon.

Lightshow · Joined: 04 Nov 2011 Posts: 3666 Location: Calgary

If the 3 screws do clamp the focus ring to the helicoid, set focus so that infinity is sharp, loosen the screws a bit, carefully turn the focus ring to lineup with infinity but not have the helicoid turn, and tighten the screws again, double check infinity and repeat if required.

The another possibility is the helicoid was put together incorrectly, off by a few degrees.

casualcollector · Posted: Sat Jan 10, 2015 1:23 am Post subject:

I've checked mine out and it has the same three small and one large screws. The large screw is the focus stop. Remove it and the lens will focus past infinity and past minimum. I suggest not messing with it. If you focus close to the point that the threads disengage, you will have a difficult time getting the lens back together correctly. As for the three small screws, follow Lightshow's suggestion. Hope that helps.

dallypost · Joined: 07 Jan 2015 Posts: 8 Location: Rockland, Idaho

It took me a little while to get back to this lens. I repaired it as you recommended and am getting some really nice video through it. Thanks for the assist.

Lance

dallypost · Joined: 07 Jan 2015 Posts: 8 Location: Rockland, Idaho

Free lens deals can be ... awesome!

dallypost · Joined: 07 Jan 2015 Posts: 8 Location: Rockland, Idaho

Now if you lens wizards don't mind, I have another lens issue for you, http://forum.mflenses.com/nikkor-180-f2-8-t69787.html