Contax lenses used on Nikon cameras.

[rbsinto]

I understand that while Contax, and lenses made for Contax cameras will fit on Nikon rangefinders, because of differing pitches in the focusing threads, beyond a certain focal length, using the Contax lenses on Nikons will result in soft photos. Can anyone tell me what is the longest lens that can safely be used? Please and thank you.

 

[Xmas]

35mm, but it depends on enlargement size.

Noel

 

[Xmas]

The Kiev lenses are real cheap, a J12 35mm will work real well, if it needs a clean dont use a micro cloth, throw it away buy another.

Noel

P.S. I'm attached to all my J12s...

 

[xayraa33]

Noel is right, I use a J-12 on my S2 and it works real good.
If you find a good J-12 keep it and do not throw it out.

 

[rbsinto]

Whata fun buncha guys! I fear I may have pulled a muscle laughing so hard.
So boys. After you've wiped the tears out of your eyes, is a 35 as long a lens as I can reasonably get away with? I've got the Jupiter 8 50 f2 on my S3, and so far it's ok, but I fear a tad soft. Should I attribute that to the glass or the difference in focusing? Please and thank you.

 

[dexdog]

The softness in the images taken with the 50mm lens would be due to differences in focusing.

I remember a recent thread that discussed focusing distances and apertures for the nikon and contax lenses, but could not find it when I searched. You could probably get away with the 50mm, as long as you did not focus close up at large aperture

 

[xayraa33]

I would say the 35mm is the longest lens that is made for a Contax that you can put on your Nikon with no problem.
shimmed 50s ala Brian Sweeney can work very well at full bore.

 

[rbsinto]

Dexdog,
A couple of weeks ago I took a shot of a couple of friends across the table in a restaurant using the 50 wide open, and it was so soft that it was unusable. For now, until I win the Powerball Lottery, I'll just have to stop down the 50, and keep farther away from the subject. Lesson learned. Thanks guys.

 

[rbsinto]

Brian,
This sounds interesting, and I'm handy enough to do it. However, I don't understand your instructions. Is this shimming technique described in more detail elsewhere, or would you be so kind as to explain it in more detail so I can attempt this? Please and thank you.

 

[wes loder]

I once owned a 135mm Nikkor in RF mount that had the 'C' on the helical indicating its focus was designed for a Contax. Since I had no idea what the 'C' stood for at the time, I used it on the Nikon S2 that it came with. The results were mixed. I had sharp pictures at infinity and stopped down at medium distances, but closeup and wide open it never seemed to focus correctly. I eventually learned the reason for the problem, located a Contax owner looking for an accessory lens and sold it.

Answer: Your mileage may vary. Wide angles, as others have noted above, should not be a problem. Normals, particularly stopped down or shooting distant views, should not be a problem. Beyond that, can be a problem. The focal plane to mount distance is the same. The Nikon helical has a different pitch from the Contax due to the mechanics of linking the lens mount to the rangefinder. Shimming may disguise the problem by moving the point where the two mounts' focus match from infinity to an intermediate distance—where DOF has a better chance of disguising the difference. At least that is my take on the problem. WES

 

[rbsinto]

Brian,
Just to clarify, with the Jupiter 8 50mm f2, when I take out the optics module to reveal the shim, is the shim threaded? And if so, do I turn the shim to "push" it in or "pull" it out (as I'm looking into the lensmount end of the lens) to correct the problem?
Finally, do I give the shim a half turn to get the 0.5mm extra to correct focus?
Sorry to be a pain, but I'd like to do this right and not shoot a roll of slide and wait a week only to find out I've done it incorrectly.
Please and thank you.

 

[rbsinto]

Brian,
So, must I add an extra shim that is 0.5mm thick on top of what is already there, or do I take out the original shim, and replace it with a new one that is 0.5 mm thick?
I only want to do this once.
Please and thanks.

As an addendum to this post, years ago I worked with a thin aluminum laminate material called Octalux which comes in a number of anodized finishes, which we then laminated to a plastic substrate with contrasting vinyl adhesive graphics.
The important point is that the raw material comes in two thicknesses, 0.35mm and most important, 0.25mm.
It is sold by Sign Supply Companies to Sign Companies, and I'm sure you could get off-cuts from any sign company for a few dollars, and use it to make shims.

 

[rbsinto]

Brian,
Thanks for the help. It's all clear now and I got some Octalux from the company I used to work for, and am going to make up a shim and give it a go. I'll let you know how it goes.
thanks again for you patience with all my questions