EM34使用說明..............
Many types of rangefinders were produced during the war, not only for ground targets, but also for airborne targets. The best rangefinder for ground targets was the Coincidence rangefinder EM34 ‘Entfernungsmesser 34’ which was first developed by Carl Zeiss in Zena. Many other optic manufactures also manufactured the EM34. The first type of rangefinder developed was the EM14 and developed in the interwar period of WW1. An improved version of the EM34 was also developed and known as the EM34 but with an asterisk ‘*’ after EM34 ‘EM34*’. It was a tube like design with big leather pads on both sides to protect the objective lenses on both sides. The EM34 was transported in a padded protective locking wrap. On both ends were turn able sleeves with holes, once turned into the right place the lenses could focus through the holes. This also kept dust and dirt out from entering the lenses. A small adjustable tripod could be attached to the EM34 just behind the main eye piece. Inside the EM34 were high quality lenses and prisms made from a high quality uncoated optic glass. Just inside the right objective shutter to the right in a second shutter with a square window which is locked with a screw. When the screw is turned 90 degrees, the collar can be rotated to two different positions. When the index mark is aligned with the text ‘Berichtigung der Entfernung’, an adjustment drum for the range correction appears in the window. When the index mark is aligned with the text ‘Berichtigung der Höhe’, a similar adjustment drum appears which is used for vertical adjustments of the inverted virtual image as seen in the centrally placed rectangular window when looking through the eye piece. Another small window with the text ‘Entfernungsberichtigung’ around it is used for indication. Inside this window is an index mark with a scale running from 0 to 40, when the rangefinder is correctly adjusted it should read 40. The range adjusting drum is placed half way between the eye piece and the right side. This is used to adjust the range of an object when looking through the eye piece. The distance observed is indicated on a scale when looking through the eye piece. The optics of the rangefinder is designed to give you 11 x magnification and a 3 degree field of view. The main image comes through the left objective lens. In the middle of the view through the eye piece is a rectangular section on the upper part of the view section. The rectangular block is approximately 28 mils wide and 7 mils high. The image of the rectangle comes from the right objective lens. When using the EM34, place the tripod onto the ground and fix the EM34 onto the tripod. Open the eye piece and the lens shutters on both sides. When looking into the eye piece, find the target and keep the EM34 on the target at all times. The target will now appear upside down inside the rectangular block but it will appear offset to one side. This is because the distance of the target has not been calculated yet. When turning the range adjusting drum, the upside down image in the rectangular block with start to move offset again. When the upside down image and the correct viewed image line up with one another you have reached the correct distance and it should be indicated inside the eye piece the distance in meters. The scale is graduated up to 100000m but the best accuracy is at 2000m, once past 3000m the accuracy declines rapidly. The EM34 can also be used standing up or kneeling down using a special chest adaptor plate with straps which the tripod legs fit into giving you a sturdy platform. Each EM34 was issued with a calibration board ‘zeroing board’ made from steel with collapsible legs. On each end was a 13mm black vertical line painted in a white square for visibility. Located in the middle on top is a prismatic sight. To calibrate the EM34 you need to follow the steps below:
Unlock the screw for the adjusting drum shutter and turn the shutter until the index marks is at the text ‘Berichtigung der Höhe’.
Look into the eye piece and find something of height like a building or tree. Now move the rangefinder until you see the top of the object along the lower part of the rectangular window. Now turn the height adjustment drum until the inverted image in the window touches the same border. When it does, the height is adjusted correctly.
Place the calibration board 80 to 100 meters away in front of the EM34 and make sure both are level. Look into the prismatic sight and adjust it till the vertical line in the right is at the middle of the EM34.
Now turn the shutter further till the index text reads ‘Berichtigung der Entfernung’. With this you can now calibrate the range of the EM34.
Through the eye piece you can turn the range adjustment drum until the infinity mark on the scale is aligned with the index mark. Direct the EM34 so that the vertical line in the image is at the centre of the calibration board.
It is correctly adjusted when the left vertical line of the calibration board coincides with the right line in the inverted. If not, turn the adjusting drum both ways till it lines up correctly.
When the calibration is finished, close the shutter. The index mark should be pointing to ‘Zu’. Now turn the locking screw back 90 degrees anti clockwise as the arrow and word Sperren indicates.
