The Pentacon Six System
by TRA

Pentacon Six or Pentax 6x7?


Having eliminated the Norita, I considered the Pentax 6×7.  Should I buy one of these instead of a Pentacon Six?

A news item in the UK publication “Amateur Photographer” in the late 1960s indicated that the famous Japanese 35mm SLR manufacturer Pentax was to make a medium format 6x6 camera based on the Pentacon Six.  This turned out in fact to be the Pentax 6×7, which produced 10 exposures 55mm x 70mm on 120 film (or 20 on 220 film).  It was hailed by the manufacturers as the “ideal format” for magazine pictures, as they claimed that most 6×6 images were cropped in order to fill magazine pages.  Their literature stated that although the image size was only 21% larger than a full 6×6, once the 6×6 image had been cropped to a vertical format, the Pentax 6×7 original was in fact 50% bigger than it.

The bodies

The first impression when one picks up a Pentax 6×7 is that it is big and heavy – much bigger and heavier than the Pentacon Six.
 

Picture reproduced from Pentax publicity
published in 1976 for the German market

The Pentax 6×7 with the plain (non-metering) prism.
Note the slot (arrowed) in the shutter speed dial in which a pin from the metering prism located, in order to transfer to the meter the information on the shutter speed that has been selected .

If only Pentacon had thought to do this!  Pentacon Six lens mount users had to wait for the Exakta 66 for the camera’s shutter speed to be coupled with the TTL meter, and when it came, Exakta chose a more sophisticated electronic coupling.

The Pentax 6×7 has an electronic shutter and is totally battery dependent – if the battery fails, the camera is dead – and battery consumption is reported to be high!  The shutter is also very noisy – not suitable for wildlife shots.  The shutter speed range is the same as on the Pentacon Six: B, 1 sec – 1/1000 plus X.  Flash sync is 1/30 second – the sync speed for which the Pentacon Six was condemned by many reviewers!  However, the camera with a basic, non-metering prism was loved by some fashion photographers aiming at dynamic shots with a hand-held camera, and magazine editors loved the format.

Like the Norita, and unlike the Pentacon Six, it has an instant-return mirror.

There is no delayed action lever.

Bad vibrations

The large mirror also causes a lot of vibration (and presumably a fair proportion of the noise) at the end of its travel (just as the shutter fires!).  An “Amateur Photographer” review years later (on 23rd January 1999) said that this “will cause camera shake at speeds which you would normally consider handholdable”.  Towards the end of the 1970s a mirror lock up was added to the camera.  This enables vibration to die down before releasing the shutter – fine for macro, architectural and still-life shots, but of no use for hand-held shots or anything that moves.

A review on luminous landscape.com written in late 2001 states that further vibrations are in fact caused by the shutter itself, so even using the mirror lock up will not solve the problem:
 

“what's happened here is that the shutter has bounced, as all shutters do. So, there have effectively been two exposures. One during the opening of the shutter and the second during the closing, at which point the camera had essentially rung like a bell thus causing the second image.”

The reviewer goes on to say that that the Pentax 67 can be hand-held
 

“only with normal to short lenses, and only in very good light or with fast film”.

For most combinations of lenses and films it is a tripod-only camera.  Worse, the reviewer goes on to state:
 

“Pentax states in their manual that the tripod should weigh more than the camera. I'd say the tripod and head should weigh at least twice as much as the camera and lens combination for ultimate rigidity.” [emphasis mine]

The reviewer concludes:
 

“this is best a tripod mounted camera, especially with long lenses and slow shutter speeds” 

If you plan to take your camera out on hikes or on holiday, the implications of this are worth considering.

The viewfinders


The Pentax 6×7 and the Exakta 66, reproduced to approximately the same scale [C372-25A & scan from Pentax brochure]

The basic body does not have a pentaprism, but in practice the camera is designed for use with one – it is difficult verging on the impossible to use the camera for vertical images without one.  Many models were sold with a plain prism, although a fully-coupled TTL metering prism was available.  This is an improvement on the Pentacon Six non-coupled prism.

Interestingly, the reviewer on Luminous Landscape (see link, above) informs us that
 

“The meter prism is almost a must with this camera, but be aware that it only shows 90% of the full frame recorded on film.”
[emphasis mine]

(This is precisely the same as one of the criticisms that has been made of the Pentacon Six prisms.  See details here, at the bottom of the page.)
 
A waist level finder and a magnifying head were also available for the Pentax 6×7.  These might, in particular, be useful for macro or studio work (with horizontal images only!), not the hand-held action shots for which the Pentax 6×7 was principally advertised.

The folding “waist level” finder is on the left.  This contains a 1.6x magnifier.
The magnifying head is on the right.  It has a 1.3× magnifier, and dioptric adjustment.
 
 


The lenses

With their wide experience of lens design for their 35mm SLR cameras, Pentax were able to produce an extremely impressive range of lenses for the new format:
 

Focal Length Aperture Range Angle of view
(1)
Elements Closest Focus (m) Filter size (mm) Auto/Manual Aperture Weight (g)
35mm f/4.5 – f/22 180° 11 0.45 (2) Auto 920
55mm f/3.5 – f/22 78° 8 0.45 100 Auto 920
75mm f/4.5 – f/22 61° 5 0.7 82 Auto 600
105mm f/2.4 – f/22 45° 6 1.0 67 Auto 628
135mm (3) f/4 – f/22 36° 5 0.85 67 Auto 767
150mm f/2.8 – f/22 33° 5 1.5 67 Auto 768
200mm f/4 – f/22 26° 4 2.5 67 Auto 900
300mm f/4 – f/45 17° 5 5.0 82 Auto 1,425
400mm f/4 – f/45 12° 5 8.0 77 Manual 2,570
600mm f/4 – f/45 6 12.0 77 Manual 6,000 (4)
800mm f/4 – f/45 6 20.0 77 Manual 17,700
1000mm f/8 fixed 6 35.0 (5) Manual 6,400

(1) As the frame size and image diagonal are larger than in the 6×6 format, the angle of view is slightly wider, too.  To compare with the angle of view on 6×6 format lenses, click here.
(2) UV, Y2, O2 and R2 built in
(3) Macro lens
(4) The Pentax 6×7 may have been aimed at the dynamic user taking hand-held action shots, but no-one will be hand-holding these lenses!  Even carrying them from the car might be a problem!  The 800mm lens makes Carl Zeiss Jena's 1000mm Mirror lens seem light by comparison.  I suspect that some of these lenses were only made to order, and no doubt had prices in U.S. dollars close to the weight in grams!
(5) Y2, R2 and ND built in

In addition – rather like with the Norita – a lens with built-in leaf shutter was offered.  This enabled flash sync at all speeds.  Details are as follows:
 

Focal Length Aperture Range Angle of view Elements Closest Focus (m) Filter size (mm) Auto/Manual Aperture Weight (g)
90mm f/2.8 – f/22 53° 6 0.85 67 Auto 610

(By the 1990s, the 90mm leaf shutter lens had been withdrawn, and replaced with a much longer focal length 165mm f/4 leaf shutter lens.)

All of the lenses have Pentax’s SMC multi-coating.

Other lenses have been added over the years.

Inspired no doubt by the 1930s 35mm Contax rangefinder cameras (which had in turn been copied by Nikon in the 1950s), the Pentax 6×7 had two lens mounts: a smaller one for the shorter lenses, and outside it a larger mount for the much heavier lenses.

The accessories

An extremely wide range of accessories were produced for the Pentax 6×7.  In 1976 the following items were listed:

This was extremely impressive.  In addition, there were of course lens caps, filters, etc.

My decision

The Pentax 6×7 system was impressive.  Yet I took the decision not to buy into it.  My reasons were:

The system has continued to be developed over the decades, with both cosmetic changes and a more up-to-date metering prism.  But I have not regretted my decision since taking it – I could never realistically have afforded the system, nor have justified spending so much money, even if it had been at my disposal.  The Pentax 6×7 was and is clearly targeted at the successful professional with a large budget (which is also why most used Pentax 6×7s that are sold have had a very heavy life – be warned!).

Is it possible to modify Pentacon Six lenses so that they can be used on the Pentax 6×7?  For a consideration of this, click here

To go back to the introduction to the cameras, click here.

To return to the section on the pentaprisms, click here.

To return to the interview with the author, click here.

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© TRA November 2005
Latest revision: February 2017