Plaubel Makina II repair

RANGEFINDER ADJUSTMENT

by Jo Lommen.


 

 The Plaubel Makina II is equipped with a coupled rangefinder.
Focusing moves the lens from and to the ground glass.
By looking through the eyepiece at the rear of the rangefinder it will be possible to see two distinct image areas,
a yellow coloured wide screen with a white spot in the middle.

As the camera is focussed the rangefinder causes the central located image to move horizontally.
When the image in this area coincides with the image in the larger area, the rangefinder will be in
correct adjustment.
The image on the ground glass is exactly the image that will be the final result on your photo.
However, if the image on the ground glass, despite the fact that both images in the rangefinder coincide is not in focus,
the rangefinder needs to be readjusted.

First test

Put camera on a tripod. And for all, use only good fitting screwdrivers.

First of all we ought to know if the infinity position of the front lens in relation to the ground glass is correct.

Place the tripod with your Plaubel camera in a dimmed room with sight to the outdoors.
Turn the focusing knob while checking the image on the ground glass.
Aim on a faraway object (cloud, building, tree or lamppost) and turn the knob until a perfect focus has been obtained.
Keep it that way do not turn the focus knob again.

. infinity index and scale focusing knob and infinity adjusting screws


The index should point at the infinity mark
Now check the scale distance index, it should point to the infinity mark and at the same time the ground glass should show a crispy sharp image.
Freeze this position by turning the adjusting screws inside the camera front lens holder.
Turn both screws counter clockwise until the screw hits the inner plate of the front lens box.
Turning the focus knob further than the infinity point is now impossible. The infinity adjustment is okay now.
Next time focusing will stop automatically at the infinity position.

Second Test

Now take a look through the rangefinder. You'll see a green coloured image with a white spot in the middle.
Point the camera to a far away object and please take in consideration that infinity is far away, as far as the clouds in the sky!
50 meters is not enough to adjust for infinity. Check if the object in the clear white spot is in line. Check also on nearer objects such as the lamppost.
If no double image is visible than no calibration has to be done. To make this procedure clear I've chosen for an object nearby, the lamppost.
 

rangefinder okay.

100 % oaky

However, if the rangefinder shows a shadow or double image, the rangefinder must be calibrated.
 Vertical double image  horizontal double image

To make changes we need to remove the rangefinder cover.
It is preferable not to touch the mirrors.
However if they are very filthy you may try to clean them with a Q-Tip using a tiny bit of clean water.
Do not rub. The mirror is a surface mirror. The silver layer is on top of the mirror glass and unprotected.
You easily will rub the silver coating off, which makes the mirror and thus your rangefinder unusable.


With the cover taken off it may be a bit more difficult to see the image. If so replace the cover temporally without fastening.
Now you clearly can see the image of the subject. Take off the cover again. Remember the position of the shadow.


If the diviation is vertically you need to adjust it with the right side mirror correction.
Turn big screw (lower arrow) one turn anti clockwise.
Turn the front screw (upper arrow) until both images comes together to one image. Turn the big black screw tight again.
It might happen that while you try to adjust your hand comes in line with the mirror. In that case you can't see the subject anymore.
Try to find out how to proceed. If you manage to bring both images together check if the adjustment can't be disturbed by a light touch of the mechanism.
It should be steady.
Check again.
 

If the deviation is horizontally (photo on the right side above) than concentrate on the left mirror adjustment.
Turn the big black screw in front of the mirror a bit loose and while watching an object turn the rear screw (red arrow)  until the object comes together.
Turn big black screw tight again.

Unfortunately there are more than one rangefinder type used by Plaubel.
The next one is slightly different and so is the calibration.
On the left side 3 adjustment screws. I found out that the B screw adjust the horizontal deviation and the A screw the vertical declination.




Replace the cover and compare all scale distances with the image on the ground glass using a magnifier.

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