The Plaubel 6x9 - 120 Roll Film

Roll film HOLDER

 

 

 

 

Photo © Jo Lommen


 

 

The Roll Holder shows two knobs.
The right knob winds the take up spool, while the knob with the figures is connected to the new unexposed film roll showing the actual frame number.

 

Open the Plaubel ROLL FILM HOLDER by pulling back both spring taps on the right side. Swing the top cover to the left. This opens the inside roll film compartment. Pull out the advance knob (the one missing the figures). Grap the inner film-holder and take it out of the Roll Film Holder. Replace the empty spool by a new unexposed 120 roll film and attach the empty spool to the take up position. Attach the paper-start strip around the empty take up spool and turn the roll one round.  Place the inside roll film holder with the new film into position inside the Roll Film Holder. Make sure that both slots fit to the gears of both knobs. Check if the film moves correctly when turning the winding knob. Check if the film lays tight and still in position. Close the roll film holder cover. Check if the spring taps are in closed position. Slide the dark slide out
Now slowly turn the film advance knob. If its sticks, move the red-dotted handle and turn the knob again. Keep watching the black paper while turning. Suddenly you’ll see a piece of tape .This is the start where the film is attached to the paper. Stop winding immediately and slide the dark-slide back into closed postion. Pull out the knob with the figures and turn it until the red "0" is opposite to the red spot on the level between the two knobs, and push the knob back in position. Now turn the right knob until its stops automatically. The figure "1" should be opposite the red spot.
Now the film is in the right position to be exposed. To wind the film in its next position, just move the red dotted handle to the left to unlock the advance knob, then release the handle again and turn the advance- knob until it stops automatically at position 2.

Preferably in dimmed light !

Advance the film without the dark-slide until the tape appears, then immediately replace the dark slide in closed position.

Set knob with figures the "0" opposite the red spot.

Don't forget to put dark slide back into film holder.

With closed dark-slide, advance film by turning the right knob, until "1" is opposite the red dot. Ready to take the first photo.

The Plaubel Rangefinder

and how it works.

 

A pellicle mirror (diminutive of pellis, a skin or film) is an ultra-thin, ultra-lightweight semi-transparent mirror employed in the light path of an optical instrument, splitting the light beam into two separate beams, both of reduced light intensity. Splitting the beam allows its use for multiple purposes simultaneously. A rangefinder coupled to the focusing mechanism of a camera is such a purpose. In the middle of the last century these rangefinders were very popular with press cameras such as the Plaubel. The rangefinder cover equiped with two windows in front and one eye piece in the back is placed on top of the camera house. Inside the rangefinder you'll find two mirrors. One is a light colored fixed optical* mirror and the other one is the so called beam splitter. The beam splitter is light coloured and is fixed in a frame. The pivot-able beam splitter frame is connected by a shaft to the strut which connects the front with the middle of the camera back. While focusing the strut will move left or right and the beam splitter frame with the beam-splitter will follow this movement simultaneously.

Now while looking through the eyepiece at the rear of the rangefinder, it will be possible to see two distinct image areas, one round colored spot lying within the other which is rectangular. As the camera is focused the rangefinder mechanism will be operated in such a way as to cause the centrally located image to move horizontally. When the image in this area exactly coincides with the image in the larger area, the rangefinder will be in correct adjustment for that subject. The better the subject is illuminated, the better the contrast.

The Simple Explanation.

The Plaubel rangefinder with removed cover on the left and the schematic drawing on the right.

When the image of the subject is reflected by the mirror and it reaches the beam-splitter the image is still 100 %.

However only 50 percent will be directed to the eye. The other 50 percent travels through the beam-splitter. Let's say this is image A.

The same happens to the image of the subject which travels in a straight line through the beam splitter to the eye. Only 50 percent will reach the eye. Let's say this is image B.

The total image A+B, can be seen in the eye piece as two images. In that case the subject is out of focus. Focusing by turning the focusing knob will alter the angle of the beam splitter.

The right distance to the subject is set, if both images coinside and merge together as one image,

 

 

 

 

*) Optical mirror is a mirror with the silver coating on top of the glass.

 


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