Medium Format Lenses with the Pentacon Six Mount

by TRA

Lens mount Compatibility

 
The Pentacon Six lens mount was designed by the company KW in eastern Germany in the mid 1950s.  It is, unchanged, the mount that they designed for the Praktisix camera.  That mount was based on an upscaled version of the mount designed for the Praktina 35mm camera.  Details of this can be seen here.

Over the years, many manufacturers have made lenses that purported to be in this mount, although in some cases (principally, with lenses from the Soviet Union and the former Soviet Union!) manufacturing tolerances have been poor or the implementation has been less than accurate or even deliberately slightly different.  This can lead to unexpected difficulties in mounting some lenses on the Pentacon Six or on some of the other cameras that claim to have adopted the Pentacon Six lens mount.

This page aims to explain the possible problems, along with some other pages to which there are links on this page.

The full implementation of the specification has the following components:
  • There is a smooth tubular section with a diameter of 60mm at the rear of the lens.  This slides into the throat of the camera.
  • This tubular section has three tabs on it, equally spaced round the rear tubular section, i.e., at 120º from each other.
  • The specification details the length and thickness of these tabs and their distance from the lens flange, which is the rear surface of the lens mount that presses against the front of the camera.  This is not the rear of the lens, which projects into the camera body.
  • The specification also states how far the back of the lens can protrude into the camera, so that it does not foul the mirror.  (I am not aware of any lens in the Pentacon Six lens mount where this particular detail has caused a problem.)
  • A screw behind the top tab locates the top of the lens in a slot in the camera mount, since in the Pentacon Six mount, the lens is not rotated to fit it to the camera, but merely correctly aligned (with the help of this screw), and then a locking ring on the camera body is rotated to lock onto the three tabs.
  • A description of the mechanism that enables the camera to open the lens aperture automatically to maximum aperture, by depressing a pin on the rear surface of the lens, and to stop the lens down to the chosen aperture when the shutter is fired, by releasing the pressure on this pin.  This is normally referred to as a “Fully-Automatic Diaphragm”, which is often abbreviated to “FAD”.
  • For “FAD” lenses, there is a mechanism on the lens (a small lever or a sliding switch) that enables the user to stop the lens down to the working aperture for the purpose of metering or checking the depth of field.
Lenses made in East Germany for the Praktisix and the Pentacon Six came from Carl Zeiss Jena and Meyer-Optik, which was subsequently called “Fein Optisches Werk Görlitz” and eventually renamed “Pentacon”.

Lenses from Carl Zeis Jena and Meyer-Optik

All Zeiss lenses fully implemented this specification.  The Meyer-Optik / Pentacon lenses accurately implemented the details of the mount but did not have a fully-automatic diaphragm, so there was no retracting pin within the rear of the lens to open up the aperture and to stop it down when the camera shutter was fired.  However, all “Pentacon” lenses in the Pentacon Six mount can be mounted on Pentacon Six cameras with no problems at all.

Lenses from Arsenal in Kiev, Ukraine and some other factories in the former Soviet Union

In his book “Made in USSR: The Authentic Guide to Russian and Soviet Cameras”, Jean Loup Princelle reports (on page 222) that in 1957 the Arsenal factory started manufacturing a medium format camera that was a virtual “clone” of the Hasselblad 1600F and then of the Hasselblad 1000F camera.  They called it the “Salyut”.  A version that was imported to the UK was called the “Zenith-80”, and it subsequently had various other names, including “Kiev 80” and “Kiev 88”.  This camera has a mount that is totally incompatible with the Pentacon Six.  Over the next approximately 30 years, the same factory developed and manufactured a range of lenses for the Salyut and its successors.

From about 1971 (Princelle, p. 225), Arsenal started producing a medium format camera that they named the “Kiev 6C”.  (See further information here.)  A revised version of this camera, produced from about 1984, was named the “Kiev 60”.  (See further information here.)  The Soviets advertised this camera as having a Pentacon Six mount.

To provide lenses for this camera “all” that they needed to do was to make a series of the lenses that they already had for the Salyut/Zenith-80/Kiev080/Kiev-88, but with a Pentacon Six lens mount.  This is where the problems start.  There are two potential sources of problems:
  • The Arsenal implementation of the Pentacon Six mount on their lenses diverged slightly from the east German specification.
  • But the much greater problem is confusion as to which mount a given lens has.  Is it the Salyut mount or the Pentacon Six mount?

The design of the automatic diaphragm mechanism on Arsenal lenses is slightly different from the original Pentacon Six standard (which is fully implemented by Joseph Schneider). The pin on the back of all these the lenses should remain fully depressed when the shutter is cocked, for maximum viewing screen brightness and focussing accuracy. When the shutter is released, a lever in the camera moves back, allowing the pin to move out of the lens, stopping the lens down to the selected aperture.

In the Arsenal implementation, this pin seems to retract slightly into the lens as the lens is opened. In practice, this may mean that at an aperture 1 – 1 ½ stops before maximum, the pin is not long enough to be fully depressed by the lever in the camera body. The result? If you are using an f/2.8 lens at, say, f/8, the lever in the camera body may only open the lens to f/4, giving you a less bright viewfinder image.

A screw in the lever inside the camera is adjustable in the Pentacon Six, Exakta 66 and Kiev 60 (with difficulty!), and with a lot of fiddling it may be possible to adjust this to give both full opening and full stopping-down with all lenses.

In my Kiev 88 “B.i.G.” camera that is advertised as having a “Pentacon Six mount”, the pin on the lenses rests of a curved arc just in front of the mirror. I can’t see how to adjust this. Worse, some Kiev 88 users have experienced problems with the pin pushing back the lever, which in turn pushes back the mirror, resulting in a focusing error. I have not experienced this particular problem with my camera.

These pictures show the difference between the Salyut/Zenith-80/Kiev 80/Kiev 88 lens mounts (which are all the same as each other) and the Pentacon Six lens mount.  Both of the pictures to the right show the Arsenal Jupiter-36 250mm f/3.5 lens – and both of them were advertised as having a Pentacon Six lens mount, but only one of them actually has that mount!  The left-hand lens has the coarse screw thread of the Salyut/Kiev 88 cameras, while the one on the right has the Pentacon Six mount.  One can see here the top of the three tabs, and the locating screw behind it (above it in this photo).

These details from higher up make it easier to see the differences between the mounts, with the Salyut/Kiev 88 mount on the left and the Pentacon Six mount on the right in all of the pictures.  I have lightened the shadows in the following two images and arrowed the screw thread on the Salyut-mount lenses, so as to make it easier to see the detail.


[k88p6mnts03.jpg]


[k88p6mnts04.jpg]

In this image end-on, the lens with the Salyut/Kiev 88 mount is again on the left, and the lens with Arsenal’s version of the Pentacon Six mount is on the right.  The alignment screw behind the top tab on the Pentacon Six-mount lens is clearly visible near the top of the lens.
 

[k88p6mnts05.jpg]

This lens has the Salyut/Kiev 88, etc. lens mount.
[k88p6mnts01.jpg]

This lens has the Pentacon Six mount (in the Arsenal implementation).
[k88p6mnts02.jpg]

To make matters worse, the differences between the Cyrillic alphabet used for Russian and the Roman or Latin alphabet used for English and (with additions) other western languages, can lead to serious errors.  The following table explains:

You can see an example of a converter from the FSU with the Kiev 60/Pentacon Six mount, labelled “C”, here.   You can find more information on mounts here.

Lenses from Joseph Schneider of Bad Kreuznach

For users of the Exakta 66 camera with the TTL prism, only the lenses and 2× converter from Schneider will actuate the meter on this camera.  To achieve this, the lenses have a rotating cam that inputs into the meter the value of the selected aperture.  This cam does not prevent the Schneider lenses from being mounted on the Pentacon Six and the Kiev 60, and operating normally on them, since the cam is not in the way.

However, most of the Schneider lenses for the Exakta 66 also have another pin towards the back of the lens, and this pin can make it impossible to mount these lenses on versions of the Kiev 88 that have been modified to have a mount that is supposedly compatible with the Pentacon Six.


[AperturePin.jpg]
 
People with the Kiev 88 with Pentacon Six mount as sold by Brenner in Germany in 1995-97 (and possibly longer) will find that Schneider lenses OTHER THAN those with a maximum aperture of f/2.8 (i.e., the 80mm lenses) will not fit on the camera, because of an extra pin that tells the Exakta TTL meter the maximum aperture of the lens. This pin sticks out at an angle, not into the throat, and the problem is actually caused by the non-standard implementation of the “Pentacon Six” mount on this camera. However, these lenses DO fit on the Pentacon Six and Kiev 60 without any problems.
 
The pin indicated by the arrow in the photograph to the left transfers the maximum aperture of the lens to the Exakta 66 TTL meter, and prevents mounting lenses with the pin on Brenner’s  “Kiev B.i.G.-Six” – a Kiev 88 body with a modified Pentacon Six mount.

For a full review of Brenner's Kiev “B.i.G.-Six” click here.

I am told that there are other Kiev 88s with Pentacon Six mounts that WILL take all the Schneider lenses.  See the Postscript to the Kiev B.i.G.-Six review.

For slight matching limitations with the Joseph Schneider 2× converter, see the section on the teleconverters. 

 

Kiev 88 cameras modified “to take Pentacon Six lenses

The “flange” or “register” distance is the distance between the front face of a camera against which the base of the lens mount rests and the film.  For the Hasselblad 1600/1000F and the Kiev 88 based on it, this distance is reported to be 82.10 mm.  The flange distance for the Pentacon Six and therefore of all lenses designed to be used on it is reported to be 8mm less: 74.10 mm.  (According to some reports, the Pentacon Six flange register distance is 74.90mm, but in either case, the same problem will remain.)  The flange register distances do not include components which pass freely inside the “throat” of the mount, such as the ring which holds the three tabs on Pentacon Six lenses.

Therefore, when a Kiev 88 camera is modified to take Pentacon Six lenses, the new mount has to be recessed within the front of the camera body.  Though – by definition – Kiev 88 cameras with Pentacon Six lens mounts take Pentacon Six lenses, this does not mean that there won’t be problems, as explained above in the case of Joseph Schneider lenses that were designed for the Exakta 66 – although in that case the cause of the problem was the modification of the Pentacon Six mount specification by Schneider, when they added the maximum aperture pin for the TTL meter.

However, there can even be a problem mounting some Carl Zeiss Jena lenses on a Kiev 88 “with a Pentacon Six mount”!  The depth-of-field lever on the 50mm and 65mm Flektogon lenses is very small and located right at the back of the lens.  This lever is easily accessible when these lenses are mounted on the Pentacon Six, the Exakta 66 or the Kiev 60.  But when they are mounted on a modified Kiev 88, it is at best difficult to reach and at worst may rub with the camera mount or even make mounting the lens difficult.  See further information on this and possible solutions here.

For the same reason, it is reported that it is not possible to mount the 1000mm Carl Zeiss Jena mirror lens onto the Kiev 88CM.  See more information here.

Incompatibility problems with tilt and shift lenses

There are also some incompatibilities when using tilt and shift lenses with the Pentacon Six and Exakta 66.  See details here.

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© TRA January 2002, latest revision: August 2017