Leica Inexpensive Adapter, Nikon RF to Leica Thread Mount. ~$70.

Brian

Product of the Fifties
Just arrived in the mail, under $70 with shipping. This compares with adapters costing 3x as much.
The Amedeo adapters are works of art, his M-Mount adapter for internal mount Contax RF lenses has an indexed cam to correct the slight difference between the Zeiss 52.4mm focal length and the Leica. This Chinese adapter does not have an indexed cam, therefore is best used with Nikon S-Mount lenses.

But for $70- the focus was perfect with a Nikkor-SC 5cm F1.4 on my M Monochrom. I have not tested external mount lenses, will do a more complete test later.

 
I attempted to use the adapter with external mount lenses: found the external mount did not line up with the lens. The mechanism was about 60degrees out of phase. Then- saw the three set screws on the side of the mount. This allows the external flanges to be moved relative to the helical. I set the mount in a Zeiss 135/4 lens, aligned it all- fastened the screws back down. The person that designed the mount: A+. Assembling it: D-; Selling it for under $70: A. Conservation of inconience: 20minutes is worth the $200 saved over comparable adapters. Anyone using only internal mount lenses would not notice the difference.
 
Now- just to confuse everyone about everything: The adapter does not have an indexed cam, the RF cam moves 1:1 with the internal mount. Nikon S-Mount 5cm internal mount lenses will focus properly with the internal mount. The focus throw is 270degrees, which is the Zeiss standard. The RF cam moves from infinity to 0.9m meter with a 270degree throw. The Nikon external mount lenses cover the same range with a 260degree turn. That means that Zeiss Contax external mount lenses will focus properly with the adapter. Confused? Anyway, I was looking for an adapter to use with my Zeiss Opton 135/4 Sonnar and my Nikkor-SC 5cm F1.4 S-Mount lens. Works for me.
 
I'll post some pictures later in the week- but tested the adapter on a 1932 CZJ 13.5cm F4, Black and Nickel. Picked this lens up for "only" $99, but took some time to straighten out the bayonet mount. Somebody did some "bending" to make it work on a particular camera. It would not mount on my Contax II. Used a spanner used to straighten out dented filter rings and a "hammer" and chisel to get it back into shape. Mount on the Contax II, works on the adapter- shots with the M Monochrom show it to be in good focus throughout range. It has not been used in decades, but the glass cleaned up perfectly.
 
Some walk-around shots, now that it is starting to warm-up.

All with the 1932 Carl Zeiss Jena 13.5cm F4, wide-open.
195127
Join to see EXIF info for this image (if available)

195128
Join to see EXIF info for this image (if available)
195129
Join to see EXIF info for this image (if available)
195130
Join to see EXIF info for this image (if available)
 
Just arrived in the mail, under $70 with shipping. This compares with adapters costing 3x as much.
The Amedeo adapters are works of art, his M-Mount adapter for internal mount Contax RF lenses has an indexed cam to correct the slight difference between the Zeiss 52.4mm focal length and the Leica. This Chinese adapter does not have an indexed cam, therefore is best used with Nikon S-Mount lenses.

But for $70- the focus was perfect with a Nikkor-SC 5cm F1.4 on my M Monochrom. I have not tested external mount lenses, will do a more complete test later.

 
I have just created a website devoted to the history of Canon rangefinders 1935-1968


this covers the cameras, the lenses and some accessories.

it also has coverage of the Minolta-35 camera and lenses, as well as some other M39 lens rangefinders that I have found interesting.

You may want to have a look....

all the best Larry Huffman

huffman@gmx.com
 
Hi Brian, just picked one of these as back up to my Amedeo and I'm hoping to make it a permanent fixture to a Jupiter 9 and a permanently fixed and coded M adapter so your comments above are very useful, I had noticed the screws. I'm interested also about the Nikon comments; do you have a definitive reference about the Nikon/Contax differences and I have seen conflicting info and some of it is clearly BS (and by BS I don't mean you Brian).

Thanks Phil W
 
I knew about the differences between Nikon and Contax standards originally from a Modern Photography test done around 1972 or so. They tested a Contax II with 5cm F1.5 lens, and measured the actual focal length. It was ~52.3mm. The Leica Elmar, in the same test, was 51.6mm. I've still got that magazine, somewhere boxed up. The Russian lenses are based on the Contax standard, and most of the manufacturer's data sheets that I've seen indicate 52.4mm as the nominal focal length.

Note this plot is log-log, focus travel of the different focal length lenses.

46327294485_a5295abbfb_o.jpg
Join to see EXIF info for this image (if available)
TRAVEL by fiftyonepointsix, on Flickr

That tiny gap in the 52.4mm vs 51.6mm is enough to throw things off. The difference in the Cam of the Jupiter-9 is set for the 52.4mm standard.
 
Last edited:
Thanks Brian, I have followed many of your discussions and fully agree; these differences are clearly stated again and again in Soviet "passport" documents and measurements even if they are occasionally masked by quality variations and wear. However, what I am trying to understand is the differences between Contax and Nikon. I know the mountings are mechanically compatible but what is the actual difference between the two?

As a takeaway from everything I read above would I be right in understanding that:

1) Nikon lenses are on the Leica standard and thus this cheap adapter works because the cam is not indexed and thus moves the same distance as required to focus a Leica lens.
2) Amedeo Contax adaptors are indexed to account for the 51.6 to 52.4 difference so focus Contax/Jupiter 50s correctly.

How is it then that the external mount on this cheap adapter works with the J9 if it would normally be "expecting" an indexed cam on the inner bayonet? What you say about turning angle may explain this I think.

You did at one point above write "Confused?" I think I am half confused. I also realise that there are Nikon lenses in Contax standard to muddy the waters.

I also hear that wide angle lenses are interchangeable but I am supposing that is because of higher DOF.

One day I'd like to get a Nikon 1.4 lens but I'm not planning to risk whilst I remain ignorant :)

Thanks for any more time you may be able to waste on me.

Phil
 
The best explanation I can come up with: The Contax External Mount lenses move ~270degrees from min focus to infinity, the Nikon S-Mount lenses move ~260 degrees from the same min focus to infinity. The adapter's helical that translates rotational motion of the lens to movement of the RF Cam is calibrated for the 270degree rotation of the Contax external mount lens. But- the internal mount lens does not have this translation of rotation to movement of the optics, it is just 1:1 with the RF cam of the adapter. That RF Cam's linear motion is designed with the 51.6mm standard of the Leica.

Wide-Angle lenses made for Nikon S-Mount and Contax mount also benefit from adjusting the Shim of the lens. I've adapted J-12 Contax mount lenses to the Nikon, and a 3.5cm F2.5 Nikkor for the Contax.
 
Hi Brian, thanks a lot for this info, I think I will spend my weekend measuring and twisting on my ever-growing collection of adapters. At the end of the day the important thing is identifying which works with what I suppose, but at least it may give me an incentive to reassemble my J9 (Contax/Kiev) which has been in bits for months.
 
I am thinking about buying this adapter. I plan on using it on a screw mount leica with Zeiss Sonnar 50/1.5. Do you have any experience or tips on shimming this lens to compensate for the 0.8 mm difference? I have done this with my Jupiter 8 before but I have not yet held the sonnar so I can not tell if it would be possible. Also, I did not find any info on the internet. Thanks.
 
The post-war Carl Zeiss 50mm F1.5 is easy to adjust: the optics module is held into the mount using a retaining ring. You will need a spanner to take it out, and might need to take out the rear module as well- I've had that happen if the metal gets bent. The module comes out, be careful of the guide pin that you see on the side of the mount- looks like a flat head screw. Once out, you will see the variable stand-off ring that controls how the optics module sits in the mount. Unscrew it about 1/4 turn, and reassemble. That usually takes care of the difference in focus.
 
Thank you for the reply Brian. I forgot to mention my Sonnar would be the pre-war (carl zeiss jena) model from 1936. I assume that there are some differences in construction of the pre-war lenses but the process would be rather similiar to what you have described.?
 
The pre-war lenses are more difficult to "shim" because the optics screw into the mount. Change the shim- the aperture ring does not line up like it did before.

My advice is to test the lens first, wide-open at 1m and wide-open at 100m. For the close-in test, use a ruler so you can measure how far the actual focus is. Jason Howe has my documentation uploaded, including computing the change in shim.


Brian
 
I found a design flaw in this adapter that was easily corrected. I used the adapter with a Nikkor 5cm F1.4 and a Zeiss 13.5cm F4 Sonnar: both of these lenses have rear elements far enough back in the lens for the problem to not manifest itself.
This week, I picked up a Contax Mount Carl Zeiss Jena 8.5cm F4 Triotar, and uncommon lens. Maybe a few thousand made in Contax mount. I put it on the Adapter, and got some horrible flare. I cleaned the rear element a second time, nothing should have caused these problems:

G1020019.jpg
Join to see EXIF info for this image (if available)
G1020020.jpg
Join to see EXIF info for this image (if available)
G1020028.jpg
Join to see EXIF info for this image (if available)


Then looked at the back of the adapter: shiny metal. No paint, no light baffles. The Triotar is an anastigmat, not a telephoto design. Basically, a larger format lens on a 35mm camera. The image circle illuminated the shiny metal of the RF cam of the adapter.

Sharpie to the Rescue.
 
So- Not flare, but reflections. Problem solved in a few minutes. Now all I cannot figure out is why Zeiss made so few of these lenses. It's really nice. This one was under $100, did have some internal haze. That was another 10 minute job, done as soon as the lens was out of the box. This lens is 3 elements in 3 groups, has a Bloom on the glass that acts as a lens coating.

All shots wide-open.
G1020046.jpg
Join to see EXIF info for this image (if available)
G1020051.jpg
Join to see EXIF info for this image (if available)
G1020043.jpg
Join to see EXIF info for this image (if available)
 
Back
Top