Medium Format Lenses with the Pentacon Six Mount
A comparative test
by TRA

500-560mm

500mm

To achieve these focal lengths in my original tests in 2002 I used these lenses:
500mm f/5.6 MC Pentacon
250mm f/3.5 Arsenal Jupiter-36B + Arsenal 2× converter
250mm f/5.6 Joseph Schneider MC Tele-Xenar + Schneider 2× converter

And, in the Hasselblad mount: 250mm f/5.6 Carl Zeiss Oberkochen Sonnar + Vivitar 2× converter

In 2007 I did further tests with 500mm and 600mm lenses, and the results of those tests start here.

In 2019 the results of tests with the 500mm Novoflex Noflexar lens were added (see below on this page).



[C308-9: From left to right: 250mm f/5.6 Joseph Schneider MC Tele-Xenar + Schneider 2× converter, 250mm f/3.5 Arsenal Jupiter-36B + Arsenal 2× converter, 500mm f/5.6 MC Pentacon and 250mm f/5.6 Carl Zeiss Oberkochen Sonnar + Vivitar 2× converter in Hasselblad mount]

Arsenal also make a 500mm APO lens that has received very positive reviews, although it is quite hard to find and therefore generally expensive.  It can be seen here and the results of tests with it can be seen here.

Shooting images with lenses of between 500 and 1000mm was a real test for my tripods, and I would say that they (the tripods!) did not reliably pass the test! In these lighting conditions, using an aperture of f/11 with 160 ISO film required an exposure of 1/30 sec, where prudence would have led to a 1/500 or a 1/1000. If sometimes the image at f/11 did not appear to be as sharp at the image at maximum aperture, it was in part an indication of the high quality of the lens at maximum aperture, and in part a demonstration that the tripod failed to hold the camera still enough.

Let’s not waste any time: the Carl Zeiss Oberkochen Sonnar + Vivitar 2× converter came out on top, although the fact that the lab printed these particular shots darker does help them to appear sharper, especially in the areas of highlight detail.  As this Sonnar lens was not the top-performer amongst the 250mm lenses, this is down to the superb quality delivered by the Vivitar converter.



[C308-34: The Hasselblad 500C with the Carl Zeiss Oberkochen Sonnar and Vivitar 2× converter.
The camera is here fitted with the Arsenal TTL prism supplied with the Kiev 88.]

The 500mm Pentacon is very close to it, even at maximum aperture!  At f/11 there is a further slight increase in sharpness.  (It can only be slight, with such excellent results at f/5.6!)  If the lab had printed the pictures darker, they would probably have matched the resolving power of the Sonnar + Vivitar, both at full aperture and stopped down to f/11.  The Pentacon lens has the advantage of being an f/5.6 lens.  Using the CZO Sonnar or Schneider 250mm lenses fully open with a 2× converter results in an effective maximum aperture of f/11!


[C306-7: The 500mm Pentacon lens mounted on a Pentacon Six]





At maximum aperture, the Schneider 250mm Tele-Xenar + Schneider 2× converter combination is visibly behind the outstanding performance of the CZO Sonnar/Vivitar, in both contrast and sharpness, which is surprising as on its own the Schneider lens beat the Zeiss.  At f/11, the Schneider combination is significantly sharper, but still behind the Sonnar/Vivitar.  I shot this twice, and one shot was spoilt by camera movement, even though I was using a tripod.  Again, if the lab had matched the print density with those they produced for the Sonnar/Vivitar, the difference would have been harder to see.
 
  [C308-35: The Schneider Tele-Xenar 250mm lens with Schneider 2× converter, mounted on an Exakta 66]


[C302-7: 500mm Pentacon at f/11  1/60 sec]


[C306-11: The Arsenal Jupiter 250mm lens with Arsenal 2× converter, mounted on a Kiev 60]

Using the Arsenal 250mm Jupiter + Arsenal 2× converter resulted in two very satisfactory shots.  Even at maximum aperture, the image is pleasingly sharp, quite remarkable, considering that this is an f/3.5 lens.  Stopping down to f/11 does sharpen up some detail slightly, but it is difficult to see.  This is where I begin to wonder about the rigidity of the tripod: the full aperture shot was exposed at 1/500 (!) (under-exposing the negative deliberately by half a stop), while the f/11 shot was exposed at a mere 1/30 (with Mirror Lock Up on the Pentacon Six).

How would I rank these four lenses?  As I said at the start, the CZO Sonnar/Vivitar comes out top.  Who is second?  It’s not easy to say, but the Pentacon is just ahead of the other two.  Then comes the Schneider combination, then the Arsenal lens + converter.

500mm Novoflex Noflexar


In spite of its long focal length, this large pistol-grip lens is designed for speedy use hand-held.  As the aperture is totally manual, it is also designed to give good resolution at maximum aperture.  Just squeeze the lens to focus, and fire the shutter.  See the overview of the Novoflex lenses for the Pentacon Six, starting here.  However, as I wanted to test a range of apertures, and to minimise differences in framing between one image and another, I mounted the lens on a tripod for these tests.  I went back to the Market Square in Hitchin.  We can see that the ownership of the Tea & Coffee House has changed hands.  It may be that the building has been repainted since the original shots 16 or 17 years earlier, or perhaps the prints from which I scanned the test results in 2001 and 2002 were slightly pink.  For these Novoflex tests, I have scanned from the negatives.


All of these 500mm Noflexar images were shot on a Pentacon Six with Fuji PRO160NS film in July 2018.

At maximum aperture: f/5.6 (1/250 sec)
[Nov_500_f5pt6.jpg (C561-9)]

One stop down: f/8 (1/250 sec)
[Nov_500_f8.jpg (C561_10)]

Two stops down: f/11 (1/250 sec)
[Nov_500_f11.jpg (C561_11-12)]

Three stops down: f/16 (1/125 sec)
This is a slow speed for a lens of this focal length, which is why I used a tripod.  The lens also stops down all the way to f/32, but I decided that in most circumstances users were unlikely to stop down the lens that far.
[Nov_500_f16.jpg (C561-14-15)]
As with the 240mm Noflexar, we note a small amount of vignetting, which in these images is more obvious in the top left-hand corner.  The vignetting appears to become sharper, but not larger, as the lens is stopped down.  There is also a small amount of vignetting across the full width of the bottom of the image.  Perhaps I have simply scanned too large an area, remembering that, according to no lesser an authority than Hasselblad, the usable dimensions of a “6×6” image are in fact 54mm × 54mm.

We have seen elsewhere (here, scroll down) that the maximum aperture of this lens was in fact subsequently calculated to be f/6.3.  Perhaps this is partly why the same shutter speed gave an exposure well within the lattitude of the film for both the maximum aperture and for f8.  In fact, as I re-metered, I found that 1/250 sec was the closest speed for the f/11 shot, too.

To the right we see a greatly-enlarged detail from near the left-hand edge of the image shot at maximum aperture.  The results are excellent, and definitely justify the manufacturer’s claim that this lens can be confidently used at maximum aperture.  Even with the relatively slow-speed film used here, the midsummer British sunshine permitted a shutter speed of 1/250 second at maximum aperture.  With careful shooting technique and the remarkable Novoflex rifle-stock mount and pistol grip, it should be possible to obtain sharp images when the camera is hand-held, even at this speed.  (The normal hand-held minimum speed for a 500mm lens is generally considered to be 1/500 sec.)

At the massive degree of enlargement shown here on the right, we can see some chromatic aberrations (colour fringeing).  However, at normal degrees of enlargement, this is not likely to be visible at normal viewing distances.

Detail at maximum aperture, f/5.6
[Nov_500_f5pt6L.jpg (C561-9, cropped)]

 
500mm Kilfitt/Zoomar Sport Reflectar

We describe two versions of this lens here.  The two versions described are referred to by their prefix codes, 278 and 292, respectively.

Version 278

The images made with version 278 of this lens were shot on a Pentacon Six with Fuji PRO160NS film in July 2018.  Information received indicated that this lens would produce images that suffered from vignetting (darkening of the corners) on 6 ×6 format, both because of the filter wheel and the use of the lens hood or shade.


500mm Sport Reflectar with shade fully forward f/5.6 (1/250 sec)
There is definitely some vignetting here, visible in all four corners, but is it due to the lens hood, which is fully forward here, or to the filter wheel/other design features of the lens?
[SportRefl_278_shade_fwd.jpg (C561-6)]

500mm Sport Reflectar with shade fully back f/5.6 (1/250 sec)
The vignetting does not appear to have decreased, so it looks as though the lens hood or shade is not to blame, or at least, not alone to blame.  Coverage appears adequate for 6 × 4.5, but not for 6 × 6.
[SportRefl_278_shade_back.jpg (C561-4)]

Detail with shade back, f/5.6 (1/250 sec)
As expected with a mirror lens, we do see the absence of chromatic aberrations that are visible 
if the image is enlarged enough with most non-mirror lenses.
[SportRefl_278_shade_backL.jpg (C561-4, cropped)]
Version 292

The images made with version 292 of this lens were shot on a Pentacon Six with Fuji PRO160NS film in September 2018.


Shot at 1/125 sec.  This is a slow speed for a lens of this focal length, which is why I used a tripod.
I clearly got the camera slightly crooked here
[SportRefl_292.jpg (C562-13)]
These tests certainly confirm that there is some vignetting on medium format with the older version of the Kilfitt/Zoomar Sport Reflectar (Version 278).  The tiny hint of vignetting seen here with the newer, 292, version of the lens is probably an indication that I have scanned too large an area.  If I had scanned 54mm × 54mm, it would probably not have been visible.

To the right we see a greatly-enlarged detail from near the left-hand edge of the image shot.  I have taken advantage of the opportunity provided by cropping to straighten up the image.  Again, we notice the absence of chromatic aberrations.

This image looks fractionally less sharp than the image shot with the older version, 278, of the lens, above.  However, this is probably a consequence of the slow shutter speed, or possibly a slight focussing error.  With non-mirror lenses, a minor focussing error can be overcome by using a smaller aperture.  However, mirror lenses do not have a diaphragm that would make this possible.

Mirror lenses have the marked advantage of being generally much shorter and much lighter than non-mirror equivalents.  I took these two Sport Reflectar
lenses with me the same day that I took the 500mm Novoflex Noflexar lens reported on above, and the mirror lenses were much easier to handle.  This may of course be because I mounted the Noflexar lens onto the tripod, whereas it is really designed to be used hand-held (with the rifle-stock).

Detail from the 292 image (1/125 sec)
[SportRefl_292L.jpg (C562-13, cropped)]

 
560mm

Marrying the 140-280mm Schneider Variogon with the Schneider 2× converter yields the longest focal length designed by Schneider for the Exakta 66.  At full aperture (f/5.6), the results are excellent: sharp, contrasty and detailed, right across the frame.  The fact that my f/11 shot shows no improvement is both a testament to the sharpness of the lens at full aperture and no doubt an indication that the tripod was not up to the challenge of holding such a long lens totally still with a very slow exposure (1/30 sec at f/11, as opposed to 1/125 with the maximum-aperture shot).  The moral of the story: with this degree of magnification of the subject, a remarkably sturdy tripod (I thought mine was good!) and high-speed film are needed.  It also helps to work slowly.

[C306- 10: The 140-280mm Variogon with Schneider 2× converter on the Exakta 66]

To read a report on a sturdier tripod for these longer lenses, click here.



[C302-13: 140-280mm f/5.6 Joseph Schneider MC Variogon at 280mm + Schneider 2× converter f/11 1/30 sec]
 
To go on to the next section, click below.

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© TRA January 2002  Latest revision: February 2019