Goltz & Breutmann

MENTOR

 

In the year 1898 Hugo Breutman founded his camera factory in Berlin. Franz Goltz joined the company  in 1899. It is not sure whether the cameras, equipped with focal plane shutter, were made in cooperation with Goerz  and Ottomar Anschuetz or not. The successor of Franz Goltz, Gustav Adolf Heinrich, initiated to move the factory to Dresden. At that time Dresden was already a well known center of camera industry. During the first world war, the factory  mainly produced cameras for aerial photography. After that period, it was hard to come back again in civilian camera business, but they kept producing single lens reflex  and strut folding cameras. In the year 1921 the name was changed in “Mentor Kamera Fabrik – Goltz & Breutman” . After the dead of  Gustav Adolf Heinrich, the continuation of the company was uncertain, until Rudolf Grosser took over the company, or what was left of it and started up again in February 1944, with 15 employers. The bombardment from 13/14 February 1945 destroyed the factory completely.

The company mainly manufactured single lens reflex cameras, equipped with the fast focal plane shutter, more than any other camera manufacturer in the world, except the Graflex Company. The camera body was a cube, made of wood and aluminum, covered with leather and a fold up viewing hood. Bellows and lens-board focus from some 40 cm to infinite, mostly with f 4,5 Tessar, Heliar and Xenar. The picture on the left  shows the cube shaped camera without hood, ground-glass and the aluminum right side.  

The mechanism to set the focal plane shutter.

Where A is the mechanism to set the  width between the 2 roller blinds. It works clockwise and anti clockwise. B disk shows the slit opening. C is the winding mechanism to cock the shutter and moving the roller blinds in the upper position. G= release. D= Set the spring tension by turning it anti clockwise to improve it and clockwise to lower the tension. E Displays the tension figures. F= sets “I” for Instant or “T” for Time exposures  

 

"M"=Moment Shutter time. 

"B"=Beliebig (German) = appropriate

 "Z"=Zeit (German) = Time = push the release knob to open shutter. To close the shutter again, press shutter release knob once again.

 

So, if the switch is set in it's "T" position, it lifts up the mirror, holds it in that position and, at the same time, sets a ratchet in a position to  prohibit the immediate following of the second blind when firing the shutter. In fact the shutter-movement is split into two movements.

To make a Time exposure;

      1)       Set the switch in "T" position.

      2)       Pull the winding/select knob and turn the time-select disc on "T".

                 It has become a select knob. This sets the opening of the slit.

                 Because of the "T" position, the slit is opened to its maximum = equal to the image size.           

      3)       Push the knob back. It's a winding-knob now and turn it clockwise. By turning it, the upper blind is wind up on the upper shaft. At the same time the lower blind is drawn up by the two straps connected to the 2nd upper shaft, which is turning simultaneously with the first upper shaft.

                        The upper blind is brought in its position followed by the lower blind and within between the both blinds,.. the adjusted slit.  

 

               4)      When firing the shutter, first of all the lower blind, drawn by the spring tension of the lower shaft, rolls to its position on the shaft,

                        It is stopped by the straps, now on maximum length, attached to the upper blind and the upper shaft, which is still blocked. Now the slit is open. By firing the shutter again, the upper blind comes down by releasing the blockade and drawn down by the spring of the lower blind.

The exposure is done.

 

The tension of the shutter-spring (the lower shaft-spring) should be enough to draw the upper blind completely down in the "T" position as described above, with the select-disc on "1".

 

After exposing the shutter is down. There should be enough tension to hold the shutter plane tight. You can study how the upper blind is connected  to the 1st upper blind. By turning the winding knob, the upper blind goes up. When it reaches the upper side of the image-sized back, stop it. The slit is open to its maximum. Now you can see the two straps connected to the 2nd shaft. By turning further, the upper 1st. shaft roles the upper blind and the upper 2nd shaft rolls the straps, just until the lower blind reaches the upper side of the mirror box. The lower blind cannot go further. End of lower-blind.

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