10.5cm f/2.5 + S3 Focus Issue

[Joe L]

I just acquired a Nikon 10.5cm f/2.5 lens to go with an S3 2000. The lens will not focus closer than 6 feet while mounted on the camera; off camera, it will focus throughout its range. Has anyone else experienced this behavior? I appreciate any advice you can provide!

 

[splitimageview]

Maybe not mounted properly? make sure to put the lens on infinity before mounting.

 

[Joe L]

I triple checked that both the body and the lens were set to infinity, and held the focus wheel still as I mounted the lens. Still the same issue.

I am thinking it’s related to that squeaky helicoid. I also picked up a 3.5cm f/1.8, and definitely feel the helicoid getting harder turn as I approach close focus. I also have found that slowly moving focus back and forth on the 10.5cm while mounted to the camera will have it slowly inch closer to close focus - now about 5.5 feet.

I am definitely going to try lubricating the helicoid from behind with lighter fluid, but the tightness is leading me to believe that Jon’s suggestion was right, that the helicoid will need some servicing.

 

[Joe L]

A little extra information - while the lens slowly would start focusing closer, when I went to remove it, I had some difficulty getting it back off the camera, almost like there was some binding between the camera and lens and that I had to rotate it further than usual to remove it. I’m starting to wonder whether there’s something amiss with the lens, or if maybe it’s slipping a thread or something?

One other thought, after reading Richard Haw’s article on this lens - maybe the rangefinder can in the lens is amiss?

 

[Sonnar Brian]

I would try the lens on a second camera if at all possible. It might be misassembled. Check that the spring loaded mechanism of the lens is moving freely. Frustrating- but do not force things.

 

[Joe L]

No second camera available, but I do have a 3.5cm f/2.5 available, which exhibits similar behavior to the 10.5cm on the same S3. The spring loaded section (the black ring) seems to move in and out without issue when I press on either side with my fingers. If I press on one side, it doesn’t move as easily.

 

[jonmanjiro]

My guess is the spring loaded sleeve around the rear element is not seating properly in the camera mount. Are there any burrs on the rear facing (mount facing) sloped corners of that spring loaded sleeve (I think I can see one in that photo above - indicated by the arrow below)? If so, try sanding it (them?) down very slightly so that the corner is smooth and try remounting the lens.

Edit: on second thought, if your 35/2.5 is exhibiting the same behaviour, the mount on the camera might be the problem (and be the cause of that burr on the spring loaded sleeve). Are there any burred edges around the inner side of the mount on the camera where that sleeve on the lens slots in that would catch so the sleeve does not seat properly? (A machining error on the inner part of the mount was the cause of that early S3 2000 recall).

 

[jonmanjiro]

Regarding the cause potentially being the mount, check around the inner circumference of the mount to see if there's a protrusion or burr here where the front and rear parts of the mount meet (FYI this is the adapter Amedeo made for me using an SP 2005 mount). The surface should be completely flat and smooth from top to bottom so the sleeve around the lens can smoothly slide in and sit flush in the mount.

Also, take the back off your camera, set the camera to T and try mounting the 105 f2.5 lens. You should be able to see whether the sleeve around the rear of the lens is sitting flush into the mount properly. If its sitting at an angle, that's your problem.

 

[Joe L]

My apologies for a slow reply - it's been busy around here. I'll look at the mount tonight, but when I took a quick look a few days ago, the mount looked smooth.

 

[Joe L]

Ok, so here's what I've seen:

- The mount looks perfectly machined. There's a roll of film in it (my wife wanted to try it out and I didn't tell her I needed to see through the back, to that part needs to wait until I finish the roll. It's Fuji Velvia 50, so not a roll cheap enough to throw away. (Is any roll that cheap anymore?)
- The 35mm f/2.5 no longer exhibits any resistance anywhere. It's my favorite lens, feel-wise, as it feels damped like Ai-S lenses (which are my favorite lenses to manual focus - I bought a brand-new 50mm f/1.2 Ai-S in 2019, and it feels like heaven to focus!)
- The 105mm f/2.5 is odd - Now, instead of resistance, it usually turns from infinity to close focus, but the focus wheel and the rangefinder spot stop moving past 6 feet. However, sometimes that doesn't happen and it couples for the full focus distance. I'm going to contact CameraQuest and see if he's open to new repairs as I think this behavior is beyond my acumen to resolve.