The Pentacon Six System
by TRA

The Zoomar 170-320mm f/4 lens for the Pentacon Six
 


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This lens was made in the highly-esteemed Kilfitt factory in Munich in southern (West) Germany, apparently starting in the late 1960s.  The Zoomar 170-320mm was the first zoom lens for a Medium Format camera.  It has a total zoom range of not quite 2× (a little over 1.88×).

It is reported that when Heinz Kilfitt retired in 1968, the Kilfitt company was sold to the American Zoomar company that re-branded the lens range with the name “Zoomar”.  However, it would appear that the lenses were still manufactured in Munich.  This lens bears the engraving “ZOOMAR MUENCHEN RAPID-FOCUS-TELE-ZOOMAR F/4 170mm-320mm Nr. [and the serial number]”.  “MUENCHEN” is a way of transcribing the German name for Munich, München, when the u-umlaut (“ü”) is not available on the keyboard (or in former times, with telegrams, for instance).  The lens is also engraved “Lens made in West Germany” on the collar for the tripod plate.

Zoom lenses for Medium Format cameras have always been rare, expensive, large and heavy, and this lens is no exception to that rule.

This lens was available for a range of Medium Format cameras with focal plane shutters.  For use on the Praktisix/Pentacon Six it requires the “WESI” mount on a WE base.  The WE base is held in place with four screws, and both the base and the mount can be changed if required, in order to mount the lens on other cameras – always assuming that you can find the appropriate mount or can get one made.

The weight of this lens with the Praktisix/Pentacon Six mount in place is 3080g.  Its minimum length when mounted on the Pentacon Six from the front plate of the camera is 31.8 cm (a little over 12 inches).  Its maximum length on full zoom and closest focus is 46.8 cm (a little over 18 inches).  Its largest diameter: is 101mm (approx 4 inches).  To this must be added the size of the tripod-mounting plate or platform.
 
The aperture

This is a manual aperture lens, so there is no automatic lens aperture operation and no aperture pin.  The maximum aperture is f/4, which is large for a medium format lens of the focal lengths covered by this lens.  The minimum aperture is f/22

The aperture ring is the ring nearest the back of the lens (closest to the camera).

A ring immediately in front of the aperture ring engages and dis-engages the click-stop mechanism:

  • with this ring rotated fully to the left, with its little red dot aligned with the aperture index mark, as one closes down the lens, it will click at each aperture position, enabling the user to count the f/ stops without needing to take his or her eye from the viewfinder when stopping down to an f/ stop determined by a meter reading.
  • with this ring rotated fully to the right, the aperture ring can be smoothly rotated without engaging in the aperture détente settings.  This may be preferable for more exact settings that may be fractionally off an f/ stop position.
Since TTL stop-down metering with the Pentacon Six TTL prism is my preferred method of working, either of these positions is fine for me.

Markings on the lens

Apart from the name, country of manufacture and aperture values, there is no other lettering on the lens: no indication of focussing distance, no index mark and no indication of the zoom setting.  In consequence of this, there is of course also no depth-of-field scale.  This is not surprising, since the the depth of field would vary with the zoom setting.  Subsequent manufacturers sought to overcome this with diagonal lines running along the barrel and/or lines of different colours, but in practice these are usually difficult to read, so that most users end up doing what users of this lens must do: focus and compose on the focussing screen in the camera – which is what one is meant to do with SLRs, anyway.

It is a significant design achievement that this lens holds its focus throughout the whole zoom range. 

Aperture click-stop engagement ring (arrowed)
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Rapid Focus
 

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This lens is described as “Rapid focus”: note the long chrome-colour lever that is here visible in the image to the left, on the left-hand side of the lens.  Press this lever down and push the front of the barrel away from you to achieve closer focus.  Releasing the lever at any point locks the focus in that position.  So this is a rectilinear (straight line) focussing action, not the helical (twisting) action that is on most manual-focus lenses.
 

Tripod platform

Underneath the lens (to the right in the image on the right here) is a large plate or platform for locking onto a tripod.  This plate is connected to a collar on the lens and can be rotated to get the camera horizontal (or to any other desired angle).

The tripod plate collar is lockable in any position with the large chrome knob that is arrowed in this photograph.

This is a large and heavy lens with a long focal length range.  One would normally expect to use it on a tripod.

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A view of the under-side of the lens reveals that the tripod plate has two tripod screw sockets in it – one for 1/4" and the other for 3/8".

Zoom control

The chrome knob just to the right of the tripod plate in this image is the zoom locking knob, which enables the zoom to be locked in any desired position.

Unlike the focussing movement, which is rectilinear, the zooming movement is helical.  In other words, the principal portion of the lens (the front sections) rotates clockwise (when viewed from the camera operator’s position) as the zoom is increased.

So the Zoomar has rectilinear focus but helical zoom action – the opposite of what was adopted, years later, by most other manufacturers of zoom lenses, who went for a standard rotating focussing ring (as on non-zoom lenses) and generally a straight push-pull zoom action.

However, the Zoomar was the first medium format zoom lens, and this is how they decided to design it.

It is possible to zoom and focus with one hand.  If one loosens the zoom locking knob (with one's left hand), one can put one's right hand round the lens and press the focus lever down to focus (by pushing and pulling), and rotate the lens, also by holding the base of the focus lever, to vary the zoom.  This makes these two actions very fast and easy.

The four extremes

Here are the four combinations of the extreme settings.  Intermediate settings are of course possible.
 

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Here the lens has minimum focus extension (i.e., the infinity setting) and minimum zoom setting (i.e., the shortest focal length available, 170mm).

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Here the lens has the maximum focus extension (i.e., the closest-focus setting) and minimum zoom setting (i.e., the shortest focal length available, 170mm).  The closest focus distance is approximately 459.5 cm (just under 4.6m).  This is a fraction over 15 ft.

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Here the lens has minimum focus extension (i.e., the infinity setting) and maximum zoom setting (i.e., the longest focal length available, 320mm).  Note that as zooming the lens rotates the front section, the focussing lever is now on the right-hand side of the lens.  The lens rotation from minimum zoom to maximum zoom is approximately 180°, with the focussing lever traversing across the top of the lens from the left to the right.

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Here the lens has the maximum focus extension (i.e., the closest-focus setting) and maximum zoom setting (i.e., the longest focal length available, 320mm).  It is in this position that the total length of the lens is the greatest – about 468 mm (a little over 18 inches) from the front plate of the camera to the front of the lens.



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The Kilfitt factory seems to have used exactly the same type of rubber rings as Novoflex for all the major control rings – aperture, zoom and focus.  About 50 years after original manufacture, the rubber is beginning to perish, again exactly as on some of the Novoflex lenses.  Note the band that has broken and is falling off in this picture (and perhaps you will see a few black spots of rubber on the white paper).  It would appear that on both Kilfitt (Zoomar) and Novoflex lenses, these rubber bands now need replacing.  Fortunately, suitable (but different) rubber is available – generally with the pyramid-shaped studded pattern.  However, the mechanical design of this lens is superb, and everything still moves as smoothly as if it were brand new.
 
The Zoomar is a coated lens, as can be appreciated from this view.

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How does this lens compare with other zoom lenses in the Pentacon Six mount?

There are a total of four zoom lenses for this camera, two from Kilfitt and the other two from Joseph Schneider of Bad Kreuznach.  For a Medium Format system, this is exceptionally good.


From left to right: Schneider 75-150mm Variogon, Schneider 140-280mm Variogon
and Zoomar (Kilfitt) 170-320mm 
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Here are some of the key details for comparison purposes:
 

Lens & focal length range Schneider 75-150mm Variogon Schneider 140-280mm Variogon Zoomar (Kilfitt) 170-320mm
Maximum aperture f/4.5 f/5.6 f/4
Minimum aperture f/32 f/32 f/22
Filter size M 86 × 1 M 95 × 1 90mm 1
Weight with front cap 2 1778g 3 2028g 3080g
Zoom range 2× 2× 1.88×
Auto-aperture operation Yes Yes No
Rotatable tripod plate collar No No Yes
Macro setting Yes Yes No
Tripod socket size 3/8" 3/8" ¼" and 3/8"

Notes
1 According to reports.  I have not been able to check this with a suitable filter.
2 Both Variogons have a lens shade, which is included in the weights.  The rear caps, which can be seen in the above photograph, were removed when the lenses were weighed, as they are not used when the lens is on the camera.
3 Weighed on the same scales as the Zoomar.  These numbers deviate slightly from the weights published by Schneider – but some slight changes of finish are documented at least with the 140-280mm Variogon in Exakta 66 mount, and these may account for the slightly larger weight difference with that lens, in comparison with the published weight.

The larger maximum aperture of the Zoomar lens and its greater focal length even compared with the longer of the two Variogons results in a lens that is significantly heavier than the two Schneider lenses

The Zoomar has a slightly shorter focal-length ratio than the two Schneider lenses, but it has greater reach than either of them.  Both Variogons were made for a range of Medium Format cameras, including some Rollei SLRs.  The 140-280mm Variogon was available for many years for Hasselblad cameras, both with a built-in shutter (for the 500C, 500C/M and other Hasselblads that required lenses to have a built-in shutter) and without it for the 2000F, which had a focal plane shutter.  For decades, it was the only zoom lens available for Hasselblad cameras, apart from the Zoomar reviewed here, which could be used with a suitable mount on Hasselblad cameras with a focal plane shutter (the 1600F, the 1000F and the 2000FC).

The Schneider Variogons were made in the Exakta 66 (1984-2000) mount, which is compatible with the Pentacon Six mount, in the latter part of the 1980s and could therefore be 20 years newer than the Zoomar reviewed here.

Test results
To the right I reproduce two pictures taken with this lens, both from the same position.  I used a Pentacon Six with a Pentacon metering pentaprism that I had not previously used, and I think that it was under-exposing by about half a stop.  The camera was on an Arca-Swiss B1-G aspherical monoball head on a Berlebach tripod.  The head and the tripod can be seen here.  The film was Fuji PRO400H and the exposure for both images was 1/250 at f/16.

Click on either image to see it larger.  With most browsers, a second click on the enlarged image will enlarge it still more.

Resolution and contrast with this lens are excellent, and we see no observable chromatic aberrations.  We can see a tiny area of vignetting in the top corners, and of course it may also be present in the bottom corners, although that part of each image is darker, so it cannot be seen.  This may merely reflect the fact that I scan until very near the edge of the frame, much further than I should, since the intended usable area of nominally “6 × 6” images, for any brand of camera, is in fact 54mm × 54mm.  (See here.)

For comparison purposes, you can see some results of taking images of the same scene with lenses of other focal lengths here, as well as on some other pages of this website. 		 

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Conclusion

This lens was a first for medium format cameras.  It is also extremely rare.  It is a worthy addition to the range of lenses available for the Pentacon Six.

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© TRA First published: April 2012 Latest revision: July 2019