Amadeo Adapters
The popularity of the Leica digital M cameras, and the resurgence of Leica film cameras, has encouraged many Leica users to explore the world of Leica compatible lenses. Other mirrorless cameras such as those from Fuji, Sony and Pentax have also encouraged users of these systems to explore older lenses, especially those in Leica Thread Mount (LTM). These older lenses often have a unique rendering to them, and the forums are filled with threads and images illustrating the differences of those lenses compared to the “too perfect” crop of current lenses.
These classic lenses from Zeiss for the Contax, Nikon for the S rangefinder cameras, and Canon in LTM are highly prized. Zeiss made a small number of lenses pre-war in LTM, and Nikon also made lenses for the original Hansa Canon, and in LTM for post-war Canons and for Nicca and Tower cameras for sale in the US by Sears Roebuck in the 50’s. Unfortunately, Zeiss lenses in LTM have always been rare and costly, and being over sixty years old at this point in time, means that finding a reasonably priced lens in good condition is almost impossible. Then there is the problem of the fake Zeiss Jena LTM lenses that come out of Eastern Europe which show up on eBay on a regular basis. Of course, there are the Jupiter lenses made in the former Soviet Union and they certainly are quite cheap, but their quality can be iffy at best. Nikon LTM lenses are a bit easier to find, but they are relatively costly as well.
Most prized by lens aficionados are the pre-war and post-war Zeiss Sonnar lenses. The Sonnar is a timeless design with a unique rendering and fantastic bokeh. The pre-war Jena lenses are usually uncoated, while the post-war Zeiss Optons are a bit sharper with better saturation due to the improved Zeiss T lens coating used by Oberkochen. The 50/1.5 and 50/1.4 Nikkors were based on the Zeiss Sonnar, but have a quite different character compared to the Zeiss lenses. These lenses made for the Contax and Nikon S bayonet cameras are much easier to find compared to the LTM versions, usually at much lower prices than their LTM cousins, but how to use them on your Leica or other mirrorless camera?
Enter the adapters made by Amedeo Muscelli of Venezuala. Amedeo makes his adapters from precision machined solid brass in two versions; one for 50mm lenses only and the original ones tested here that will take any of the bayonet lenses made for the Contax or Nikon. These adapters also come in two flavors, one for Contax and one for Nikon S. Why two versions? The simple answer is that despite all physical appearances to the contrary that the mounts are identical, the two lens systems are not compatible with each other! There are two schools of thought on what the cause of this incompatibility is. It seems that Zeiss standardized on 50.0mm nominal focal length for its normal lens when it developed the internal helicoid for its Contax bayonet mount. Nikon (Nippon Kogaku) on the other hand, had its start supplying lenses to Hansa Canon in the pre-war period. When Canon resumed production after the war and introduced an interchangeable mount 35mm camera, the company based its rangefinder body on the Leica standard nominal focal length of 51.8mm. When Nikon later introduced its own cameras based on the Zeiss Contax, it maintained the Leica/Canon standard nominal focal length of 51.8mm, but altered the helicoid travel from the Zeiss standard to accommodate the difference. Why was this done? A logical answer would be that if the fledgling Nikon S system had failed, Nikon would not have had to re-tool for the nominal 50.0mm focal length standard, which would have taken extra time and investment on their part. When Nikon launched the S series rangefinder cameras, time and money were in short supply. This expedient solution of altering the heliocoid was the right one for the time, but then the die was cast much to the chagrin of those trying to use Nikon lenses on the Contax and vice-versa. From the manufacturer’s point of view this made sense as well, since their goal was to sell their own lenses for their own cameras and not to be concerned about compatibility with a competitor’s product. As an alternative to the above explanation, according to Henry Scherer of www. zeisscamera.com, the helicoils are identical, but the Nikon body is 0.31mm thinner than the Contax. Henry presents a meticulous analysis of the Contax and Nikon mounts to support his theory on the website. The bottom line is that whatever the reason, the two mounts are incompatible and will not provide accurate focusing if the lens if a Nikon lens is mounted on the Contax and vice-versa.
With wide angle lenses, depth of field takes care of this mount discrepancy, but the problem really manifests itself with 50mm and above focal lengths, at close distances (3.5 feet) and wide open aperture. This is especially true for the 50/1.5 Sonnar and the 50/1.5 and 1.4 Nikkors. Hence the need to use the Contax adapter for Contax lenses and the Nikon adapter for Nikon lenses. By using the properly matched adapter, you will get correct focus at infinity and in the close-up range. These lenses can also exhibit “focus shift” while changing aperture after apparent focus has been achieved. Focus shift occurs when the lens actually focuses slightly in front of or behind the intended point of focus, especially in the close-up range at about three feet. Some experimentation is required to see if a particular lens has focus shift and at what apertures it occurs. Some lenses were optimized wide open at f/1.5, and some at f/2.8. Upon stopping down to f/4 and beyond, focus shift is no longer a concern.
In my own tests with my Monochrom, focus for a post-war Zeiss Sonnar 50/1.5 was spot on at f/1.5 and exhibited minimal focus shift at f/2.8. My 50/1.4 Nikkor appeared to be optimized at f/1.4, with some back focus at f/2.8. This test can be readily accomplished by setting your camera up on a tripod, laying out a yardstick on a horizontal surface on a slight incline, focusing on the midpoint of the yardstick at several apertures beginning with wide open, making an exposure at each aperture and evaluating the results on the display screen. If you are using a film camera, you will need to make careful notes for each exposure made and evaluate the developed film. Once you learn how your lens behaves, you can minimize the effect of focus shift by leaning in or out an inch or two after focusing but before making the actual exposure. This sounds complicated, but becomes second nature in actual practice. Again, with increased distance and stopped down apertures, the focus shift issue goes away on its own. But if you are the type of photographer who believes that wide open shooting is your style and the way you shoot, then you need to be aware of and master this issue. Of course, if you are using a M240 generation camera, the new SL, or a Sony A7 or similar mirrorless digital camera, focus shift can be avoided altogether.
In addition to the above mentioned focus shift issue, Zeiss and Nikon RF lenses rotate in the opposite direction to Leica when operating the focusing ring. Zeiss lenses also do not have click stops on their aperture rings as modern Leica lenses do. This can be a bit off-putting as well when first using these lenses. Mounting these lenses to the adapter is a little different as well, as you line up the lens locking tab with the red dot on the lens locking mechanism and then rotate the lens counter-clockwise until it locks into place. If you plan to use 50mm lenses only, the other adapter Amedeo makes might be a little easier to use as it has a simplified locking system and the focusing ring turns in the same direction as Leica lenses do. I also tested a Jupiter 12 35/2.8 lens and a pre-war Zeiss 135/4 Sonnar on the adapter and they functioned flawlessly. However, I was unable to get a Zeiss Opton 35/2.8 Biogon lens to either mount or focus properly with the adapter. I think this is due to some sort of mechanical incompatibility with the Leica’s rangefinder follower cam wheel. Not wanting to damage the camera, I gave up on this lens!
In corresponding with Amedeo about his adapters, I learned that he makes these adapters as a hobby and they are not his “day job” so to speak. Amazing! The adapters are very nicely machined, and although not as well finished as a typical Leica accessory, they are more than acceptable. The Amedeo adapters are available on eBay direct from Amedeo himself, user name amedeo.m. Or, if you would prefer to deal with someone in the United States and take some of the drama out of your purchase, the adapters may be purchased from Stephen Gandy at Cameraquest.
I would highly recommend Amedeo’s adapters if you would like to explore the world of Zeiss and Nikon RF lenses at a reasonable price. These lenses offer some very unique qualities, far different from the perfect (some would say boring!) lenses available today. One could say these old lenses are loaded with character, and it is always interesting to see the world through older glass. I plan on using my adapters for some comparative lens testing of the various Sonnars, Nikkors and Canon lenses with their Leica counterparts for a future issue of Viewfinder. Stay tuned!