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C/Y to Nikon lens adapter


There have been a lot of questions on many of the camera forums that I visit as to why no one makes a C/Y to Nikon lens adapter.

The standard, and reasonable answer is that the Nikon flange distance (the distance between the lens mount and the film, or sensor plane) is greater than what Contax lenses are designed for. So, if such an adapter were devised, the Contax lenses could not possibly focus at infinity.

Contax flange distance = 45.5mm
Nikon flange distance = 46.5mm

But, I would really like to use my CZ Makro Planar S 60/2.8 on my Nikon D300.

Wait, did I say Makro (Macro).

If I'm going to shoot macro, I don't care if the lens can focus at infinity.

So, off to KEH to do some shopping. I bought a Yashica 7.5mm extension tube and a Nikon 8mm extension tube.

After machining off the Contax bayonet side of the mount, I had a nice flat surface. I removed the Nikon bayonet piece from the Nikon extension tube and did some measurements on the screws. My digital caliper said 1.666mm diameter. My pitch guage said 0.35tpmm (threads per mm).

1.666 is not a standard metric size. So, I ordered a 1.6mm and 1.7mm tap (with matching pilot drills) from Victor Machinery.

After trying the taps in the threaded holes in the Nikon part, I settled on the 1.7mm size.

I carefully aligned the Nikon bayonet on the back of the Contax part so that the lens would be in the correct position after it was mounted on the camera. I drilled and tapped the holes and screwed everything together.

Off to my CZ lens collection to try it out.

OOOPS! The CZ Makro Planar S has some projections at the back that did not clear the Nikon part. The iris lever and its guard, on this lens, stick out further than the same parts on my other CZ lenses.

So, back to the machine shop (in my basement, thank you). I set up a rotary table on my mini-mill and installed a 1/8" flat face bit.

After some careful alignment of the part with the mill, I was able to machine a perfect recess in the Nikon part that would clear the projections on the back of the CZ macro lens. This, of course, is a segment of a circle, which is why one needs a rotary table

Now I can take digital macro pictures with this very excellent lens on my D300. The farthest focusing distance is about 3 feet, maybe a little more.

I haven't tested the closest focusing distance, but I know that it is more than 1:1 because of the extension tube/lens adapter.

Since the D300 cannot control the aperture of the lens, one must shoot in manual mode stopped down to the deisred aperture by using the ring on the lens. In bright sun light, focusing at f/11 is no problem. One could focus with the lens wide open and then stop down to take the exposure and the shot.

The neat thing about focusing with the lens stopped down is that you can see the depth of field.

Exposure is determined by first setting the aperture on the lens and then adjusting shutter speed until the meter on the camera is in the center of the manual exposure scale.

I'll post some pictures when spring gets here, to Minnesota, and there are suitable subjects at hand.



New Member
Excellent Job!

Hi Ron,

I am also in MN 55423.
Let us continue to discuss further into what your Macro works turned out with your D300.

I'm really intrigued by your skillful and creative adapter (Contax to F mount) as well without any optics involved.

Warm Regards,

sunnyboaz at gmail dot com


CZ/Nikon adapter

Hi Sunny,

So, I see that you are in Richfield.

I am in Prior Lake.

Glad that you liked the article.

I have also tried one of the Chinese adapters, with optics in it. I was
surprised by how good is it. The lens is coated and everything focuses to

It's not perfect but not bad and doesn't seem to add much chromatic

Tell me about your Contax.




New Member
Any pictures taken by your Macro C/Z on D300?

Hi Ron,

I was wondering if you have further interest in adapting C/Z lenses with/ without optic adapter.

Thank you again for arousing my interest in this specific area of seemingly impossible adaptation.