100 years Null-Serie

[Roland Zwiers]

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4 minutes ago, LocalHero1953 said:

It wasn't stated by me, to whom you were replying - hence my puzzlement.

Paul,

There are many misunderstandings in this thread.
But you did ask a very interesting question on film development on location in 1912.
In my response I gave you the building blocks that I have found so far.

What do you think?

Roland
 

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[LocalHero1953]

1 minute ago, Roland Zwiers said:

Paul,

There are many misunderstandings in this thread.
But you did ask a very interesting question on film development on location in 1912.
In my response I gave you the building blocks that I have found so far.

What do you think?

Roland
 

I found the discussion interesting, but I have no knowledge to bring to the table! It was the other Paul ( @pgk) who responded to your suggestions and would be better placed to comment.

[Roland Zwiers]

Paul,

I apologize.
This time the confusion is on my side 🙂

Roland

[beoon]

23 hours ago, Pyrogallol said:

unless someone finds an undiscovered notebook

Not an undiscovered notebook, but I have seen a drawing of another prototype camera. Unfortunately I have been asked not to share this drawing.

There is more information out there for sure 

Edited August 7, 2023 by beoon

[pgk]

15 hours ago, Roland Zwiers said:

For this procedure he would have had to develop and fix the film strip on location in a dark room.
In the 1910s portable dark room tents were indeed available.

On his third expedition in 1866, Samuel Bourne climbed up into the Himalayas, to the Manirung Pass and photographed the pass itself using a “Grubb C lens, fifteen inches focus, and smallest stop” (his photo reference is 1468). The pass is at 18,600 feet and at the time this was the highest altitude at which photographs had been taken. He was using wet plates which had to be prepared and processed on site. If you google the image you will find that the pass was full of snow so the problems of preparation and development were undertaken in a light proof tent and temperature was somehow elevated to allow for this processing. In comparison, by ~1910 processing on site would have been a doddle - a relatively simple thing to do even if by today's standards it was somewhat awkward. As I said before, doing sp would have saved a great deal of cost of potentially wasted film for an hour or so's awkward work - simply developing and brief fixing would have been enough as test strips would have been thrown away once a viable exposure was established.

[Roland Zwiers]

Paul,

I fully agree that in 1912 development on location cannot have been a problem as such.

But Oskar Barnack didn't just need to develop on location.
The outcome of the development procedure for his teststrip had to be representative for the development of the 60m film later on.
Otherwise the filmstrip would not do a good job as an exposure tester.

Suppose that the development procedure on location [A] was different than the development procedure [B] that would be used for the 60m film length.
In the dark room tent he could use a different temperature, different chemicals etc.
He could also prolong the development time (using a safety light) until the film strip was fully developed.
And then he would do the exposure of the 60m film in line with the best developed negative from the test strip.

Wouldn't Oskar Barnack then be running the risk that he was still making an exposure error with the 60m film when he would use development [B]?
If so, wouldn't he like to do development procedure [B] on location as well?
If so, wouldn't he need temperature control for development on location?
If so, could the many references to an adjustable electrical heating table in his worknotes of 1913 and 1914 point in this direction as well?

Roland

 

 

 

 

 

[Roland Zwiers]

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Testing the 1913 Mikro Summar

I will be off-line for a few days.
But before I go I would like to share my thoughts on the 1913 Mikro Summar, the lens used on the Ur-Leica.

Ernst Leitz (1933) explicitly places the first Leica with a 1:4,5 Summar lens in 1913.
The focal length is not specified.
This may be an indication that Oskar Barnack had experimented with both the f=42mm and the  f=64mm Mikro Summar lenses.
Ulf Richter (2009) makes clear that the focal length of the lens on the Ur-Leica is 42mm.
[According to Van Hasbroeck (1987) the lens on the Ur-Leica is a 1:4,5 Milar. I prefer to follow Leitz (1933) and Ulf Richter (2009).]
I assume that prototype 2 (used by Ernst Leitz II in 1914) made use of the same lens.
For the prototypes 3 of 1914 (‘Gebrauchsmuster’ and ‘Mustermodell für Fabrikation’) this is less obvious.

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What do we know of the origin of this 1913 Mikro Summar lens?

The Mikro Summar was introduced as a new lens in a French language catalogue in September 1906 and again in an English catalogue in 1907.
I have not been able to find the original German version.
The Mikro Summar was designed as an accessory for a plate camera that would normally be used in combination with a microscope.
For lower magnifications the microscope would be replaced by a Mikro Summar.
In the example pictures the 42mm lens is used for magnifications of 5½ to 7x.
In the Leitz catalogue the recommended magnifications vary from 1:1 to 23:1.

 

Note the use of Eosine-bathed plates so as to arrive at colour correct black-and-white pictures>

In my working hypothesis Oskar Barnack likewise self-sensitised colour-blind 35 mm films for his Ur-Leica.
I have discussed this before.

 

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[Roland Zwiers]

Now what made Oskar Barnack decide to use this highly specialized micro lens for his Ur-Leica?
Wouldn’t this be asking for trouble?
Well yes and no.
The Mikro Summar design was optimised for micro work, but would not be completely unsuitable for general photography.
One can only say that a lens designed for general photography would have had a (much) better correction for infinity.

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A probably bigger problem with the design of the Mikro Summar was that it was composed of six individual lens elements.
In a laboratory environment, it may not have been necessary to cement individual lens elements so as to avoid internal reflections.
This problem would, however, manifest itself as soon as the lens was used in broad daylight.
With six individual lens elements the Mikro Summar would lose a lot of light because of internal reflections.
These reflections would, moreover, deteriorate the contrast.
In averse situations these internal reflections would even spoil the picture with ghost images. 

In 1913 for Oskar Barnack these considerations may not have been so relevant.
He was simply looking for an experimental lens for his would-be Ur-Leica.
The Mikro Summar would cover the entire negative nicely.
Ulf Richter (2009) observes that the f=42mm Mikro Summar was short enough so that it could be collapsed inside the camera body.  
And the maximum lens opening of 1:4,5 was not too slow for hand held photography with a shutter speed of 1/40^th of a second.

 

[Roland Zwiers]

Adaptations for the Mikro Summar

In order to make use of the Mikro Summar Oskar Barnack had to make three or four adaptations.

 

• He had to create an accurate focussing mechanism so that he could focus the lens at a predetermined distance.
• He had to create an accurate aperture scale with relative f/stops (f/5, f/7 and f/10). These F-stops must have corresponded to the French aperture system of 1900.
• And he had to equip the lens with a rotating disk, so that the lens could be covered when transporting the film.

A fourth necessary adaptation would have been:

• the addition of a sun shade.

A sunshade would have shielded the lens against stray light.
However, the rotating disk in front of the Mikro Summar must have made the use of a suitable lens shade more difficult.
When one keeps in mind all these requirements, then it becomes clear that the contribution of the 1913 Mikro Summar to Leica photography is easily overlooked!

 

[Roland Zwiers]

How to make use of engraved settings?

Now the usability of a standard lens critically relies on the accuracy of its engraved values.
When a photographer wants to take a picture with aperture f/10 at a distance of 5 meters, then these settings must do what they stand for.
I will illustrate this with pictures taken with the Ur-Leica.

When one focusses a well calibrated lens at infinity, then one can expect infinity to be in focus.
But in practise a larger area is in focus than infinity alone.
This area is the depth of field.
The smaller the aperture (say f/10 instead of f/5) the bigger the addition to the depth of field.
The boundary to where the foreground becomes out-of-focus is called the hyperfocal distance.
When one focusses at the hyperfocal distance, infinity is still in focus, but one makes additional gains in the foreground.
The table below makes this clear.
For the calculations I used an optical formula that must have been well known to Oskar Barnack.

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With this information in hand it is interesting to look at two 1914 Ur-Leica pictures of a movie maker.
One must assume that the photographers (Oskar Barnack and his colleague) intended to get both the foreground and the background in focus.
How did they do this?
With a traditional plate camera they could check this on the ground glass.
But with his Ur-Leica they had to rely completely on the engraved settings of the Mikro Summar!

Oskar Barnack would have measured the distance between the camera (better: film plane) and his colleague.
Suppose this was 3,8 meter.
Then he could take the picture from that position when focussing the lens at 7,6 meter at aperture f/7.
The available light would then determine whether he could still make a handheld shot.

Question: does the Ur-leica have a facility for a time exposure?

For the second picture the photographer moved closer to the subject.
How to get both the fore- and the background in focus again?
At a distance of 2,6 meter he could have focussed on 5,3 meter using aperture f/10.
With a well calibrated lens the depth of focus should have been sufficient.
If not, then Oskar Barnack would have had to readjust the lens settings.

In this way the Mikro Summar must have done a lot of preparatory work for the ultimate success of Leica photography!

Roland

[Roland Zwiers]

Practical examples - the 1914 contact prints of Ernst Leitz II

I forgot to add some practical examples of the Mikro Summar.
But look at the picture on the left in the previous posting.
One can see that the trees on the mountain are light grey.
The same trees on the picture on the right are dark grey.
This is a sign of internal reflections in the Mikro Summar lens because of the six separate and uncoated lens elements.
A good sunshade might have prevented this.

The six pictures below are taken by Ernst Leitz II on his June 1914 visit to the USA.
One can clearly see that he used a colourblind film.
The picture in the lower right corner again shows sign of internal reflections in the Mikro Summar lens.

As far as I know the 1914 pictures by Ernst Leitz II are still available as contact prints, but never published.
This is a pity as Leica researchers like Ed Schwartzreich and Oscar Fricke may still identify the photographed locations.
So it would be very welcome when we can look at these contact prints when we visit the Leitz archive in October.

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The examples below are the pictures that Oskar Barnack took of his children and their playmates.
Photographers that used colour blind material would prefer to dress children in white outfits.
Oskar Barnack indeed dressed his daughter in white.
On the other hand the boys wear navy blue outfits.
With colour blind material (sensitive to blue) the reddish faces and the girls’ blond hair would have been darker, whereas the navy blue outfits could have been much brighter.
But on the pictures the blue is not too light and the girl’s hair is very bright, much as our eyes would see it.
This is an indication that Oskar Barnack used a colour sensitive film (self-sensitised) in combination with a yellow correction filter.

I would like to check this outcome with colour blind 35mm film myself;
what would navy blue dress and blond hair look like in bright sunshine?
Would the navy blue indeed be much brighter; would the blond hair be much darker?
Unfortunately, I am told that colour blind 35mm film is not available anymore.

An alternative test would be to use black-and-white photo paper in a film cassette for a technical camera.
E.g. the 6,5x9cm cassettes for the Linhof Technica.
That should be a good enough approximation.

Roland

 

 

 

 

 

 

 

  

 

[derleicaman]

So far this has been a very interesting discussion with many contributions from the participants here. This is exactly why I enjoy going on the LUF!

However, I think we are losing sight of a few fundamental facts, and I was struck by this in general a few years ago when I first learned of M875.

The basic facts are that Barnack was hired by Leitz on the recommendation of Emil Mechau. Mechau had worked at Carl Zeiss and there met Oscar Barnack. Mechau had been working at Zeiss on the development of a flicker free motion picture projector. Motion pictures were seen as having a huge future, and Leitz was planning on getting in on the action. Mechau left Zeiss in 1910 to work at Leitz, who showed more interest in the development of his projector than Zeiss did. Leitz needed a Master Machinist in the Microscope Department, and Mechau remembered Barnack from his time at Zeiss. Everyone knows this part of the story, where Barnack was reluctant to go to Leitz, as he suffered from poor health and felt that an employer would not be interested in someone who would have to take several months off per year because of this. Mechau was personally involved in the negotiations with Ernst Leitz I and II to hire Barnack, and the rest as they say is history.

Barnack was hired by Leitz, and began work there on January 1, 1911. Soon, Barnack began work on an all-metal 35mm motion picture camera, which Roland shows in his previous posting. As the film stocks were variable as to their light sensitivity, and as Roland points out, Barnack may have been treating the film stock to increase its sensitivity, a reliable method was needed to make a test of a short strip of film stock before shooting an entire roll of motion picture film and finding out that your “guess” on exposure was wrong! Hence, the creation of M875. It was never intended to be a full-fledged camera, merely a means of testing exposure with a short film strip. And here is where serendipity comes in. This device actually made serviceable photographs on the short strip of film! M875 as it now exists, is a light-tight housing for the short film strip, with a removable bottom cover for loading film, a tube with what appears to be a gravity shutter, and an back door flap. That’s it. There is no lens mounted on it, only a tube with a ring that can be tightened with a small screw. It is assumed this is where the lens was mounted. There is no focal plane shutter on this device, only the sliding guillotine over the body opening. One school of thought argues that the drop shutter approximates 1/40 of a second of the motion picture camera. It also should be pointed out that the 1/40 of a second for all motion picture cameras at this time was the “target” or ideal speed, when the reality was that these cameras were hand-cranked by the operator and the actual speed could vary quite a bit from the ideal. This became known as “over” or “under” cranking the camera, with the effect being some of the comical action of the subjects being seen in these early motion pictures. The other school of thought believes that a leaf shutter (Compur type) lens combination was used mounted on this tube. This would obviate the need for a focal plane shutter, and one could argue that there was a dual train of thought on the path of coming up with a functional camera. The parallel product lines of the Compur Leica and the Leica I would give some credibility to this line of reasoning. No one can absolutely know for sure exactly how M875 was used. Was it handheld, or mounted vertically to the side of the motion picture camera as some have argued to allow the drop shutter to function? Did M875 give Barnack the actual idea of the small camera he eventually developed, or did he develop this in parallel to the Ur? Again, no one knows for sure. The only thing we do know for sure is that both the Ur and M875 were developed in the short period of time after Barnack’s hiring in 1911, all the while working on the development of the motion picture camera.

The next logical step would be to make an actual camera with a lens having an adjustable aperture in a focusing mount, and a reliable shutter and advance mechanism for the film used in the camera. This was Barnack’s Lilliput camera, which we call the Ur. M875 was found in a cabinet that Barnack kept in his office at the Hausertor Werk after his death. In this cabinet, Barnack also kept various notes, drawings and note books. Barnack’s successor, Wilhelm Albert came into possession of the cabinet and its contents. At some point, Leitz included these items in its Archives, and named the exposure device M875. While not as important in the story of the Leica as the Ur, M875 nevertheless should be considered as an important stepping stone in the development of the Leica, and not forgotten.

Again, I will remind everyone that we need to examine the development of the Leica from the point of view of the time period prior to 1914, not the present day.

I have asked that M875 be made available for our visit in October, when we can all take a look at it and have it as part of our discussion.

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[Roland Zwiers]

Again, I will remind everyone that we need to examine the development of the Leica from the point of view of the time period prior to 1914, not the present day.

Bill,

I fully agree.
As far the exposure tester M875 and the Ur-Leica are concerned, my working hypothesis is rooted in primary sources prior to 1914, including Oskar Barnack's work notes. 
Post-war literature was of little use, with the exception of Gevorg Mann (1992).

For the M875 you mention two schools of thought.
I think that in my working hypothesis these are already combined.

Oskar Barnack may have started with the gravitational shutter.
When this shutter disappointed, he may very well have continued with a compound shutter in front of the lens.
That must have disappointed as well, as it would not be easy to select the right shutter speed between 1/25 and 1/50 sec.

In my working hypothesis Oskar Barnack then decided to work on an accurate focal plane shutter that could be designed for the shutter speed (say 1/40)
that corresponded with the target speed of the motion picture camera.

I fully realise that a working hypothesis may provide a coherent story line, but may still turn out to be wrong when confronted with new evidence.
That is why am eager to find new material in the Leitz archive!

Roland 

 

 

[derleicaman]

Looking at the pictures I took of M875 in the Archive last October, something is getting my attention. Why does M875 have a hinged door on a piano hinge with two lever fasteners? Compared to the Ur camera, which has a removable plate fitted with 4 removable screws. The hinged cover on M875 looks like it was added as an afterthought. The hinged cover would also allow quick access to the camera interior. Why would they need to have this? If it was installed as an afterthought after its days as an exposure tester were over, why did they add it? Testing ideas for future cameras? If so, when was this done? The production Leica I and later cameras had a little "peep hole" at the back of the camera with a replaceable cover in the vulcanite. I believe this was used to calibrate the lens to the camera for proper infinity focus.

The other thought that occurred to me was that the hinged back door did not appear on a Leica until the Leica 4 prototype just before the War. This was the prototype for the M3 camera introduced in 1954, and was a feature on all future M film cameras.

Perhaps the life of M875 was not as limited as we have all assumed. Perhaps it was a test bed to try out ideas that did not appear until many years later.

[Roland Zwiers]

Why does M875 have a hinged door on a piano hinge with two lever fasteners?

Bill,

According to primary sources from this period (!) some 35mm movie cameras had a facility to focus directly on the filmplane.
So the 35mm film itself would act as a ground glass/ focussing screen.
Oskar Barnack must have known about this feature.

In that case the first part of the filmstrip for M875 would serve as a focussing screen.
This required an open door, so that he could look at the film plane.

Next he would insert the lens (likely the Kino Tessar) and move it in position until it was in focus.
Then he would close the door and turn the film strip a few frames so as to get the film ready for exposure. 

Roland

 

[derleicaman]

1 hour ago, Roland Zwiers said:

Why does M875 have a hinged door on a piano hinge with two lever fasteners?

Bill,

According to primary sources from this period (!) some 35mm movie cameras had a facility to focus directly on the filmplane.
So the 35mm film itself would act as a ground glass/ focussing screen.
Oskar Barnack must have known about this feature.

In that case the first part of the filmstrip for M875 would serve as a focussing screen.
This required an open door, so that he could look at the film plane.

Next he would insert the lens (likely the Kino Tessar) and move it in position until it was in focus.
Then he would close the door and turn the film strip a few frames so as to get the film ready for exposure. 

Roland

 

Roland, that is a very reasonable assumption. One could also place a groundglass in the film gate to accomplish the same thing. This way, one could focus the assumed Kino Tessar lens on M875 with the back door open, before film was inserted into M875 to make the test exposure.

Now this poses an interesting question. Was the Kino Tessar the same lens used on the cine camera Barnack built? How is the lens on the cinema camera mounted to it? Is it mounted with a circular clamp like the one used on M875? A reasonable assumption would be that before exposing the film in the cine camera, the lens was removed from it and mounted on M875 to make the test exposures, and then swapped back on to the cine camera to expose the film in the motion picture. It would make sense to have M875 mounted to the side of the cine camera as Ray Morgenweck has proposed.

I have never heard of anyone ever describing the procedure of how the cine camera and M875 were used together in practice. Maybe we should ask to have the cine camera present to look at this as well.

 

Edited August 7, 2023 by derleicaman

[derleicaman]

Here is a link to Heinz Richter's article on his Barnack and Berek blog about Mechau.

https://gmpphoto.blogspot.com/2022/07/emil-mechau-and-development-of-ur-leica.html

[derleicaman]

An interesting aside about Mechau. He died only a few months after the end of the war. He was "asked" to defuse a grenade by a Soviet soldier, and died when it exploded on him!

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Hallo,

Look here: Interesting Leica gear

[pgk]

22 hours ago, Roland Zwiers said:

Paul,

I fully agree that in 1912 development on location cannot have been a problem as such.

But Oskar Barnack didn't just need to develop on location.
The outcome of the development procedure for his teststrip had to be representative for the development of the 60m film later on.
Otherwise the filmstrip would not do a good job as an exposure tester.

Barnack's 'problem' with exposure testing would not have been unique! Even early on, film making was starting to become lucrative and would have required certainty of exposure. It might well be worth researching how the movie cameramen of the day dealt with this problem although I'd guess a lot simply shot a length of film through their movie camera and then processed it on site. But this would have been expensive, wasteful and time consuming. Have a very short strip which could be processed quickly to ensure correct exposure ('clip testing') makes better sense all ways around, and film labs in London certainly offered a 'clip test' service into at least the 1980s to ensure exposure and colour consistency depending upon film batches. I don't see consistency being a major obstacle to anyone seriously trying to determine exposure even ~1912. Barnack was clearly a logical thinker and part of his thought process would have been about film sensitivity and exposure assessment and coming up with a consistent test method. To me the M875 fits in with this thought process very well.

[pippy]

3 hours ago, pgk said:

...film labs in London certainly offered a 'clip test' service into at least the 1980s...

They still do. Pretty much an essential service and not just for roll-film. When using (say) 5"x4" E6 it's common practice to shoot one extra sheet at the 'correct' exposure and hold development of three others (usually bracketed at -1/2 Stop : Correct : +1/2 Stop) until this first sheet has been examined.

Philip.

Edited August 8, 2023 by pippy