Part of KM optic?

[Skylighter]

Can you guys help me out with this KM optic part? As a U.S. collector I do not know anything about it. Where was it used for? Is it complete? And what is an approximate value for this piece? It is not in my possesion (I am asking it for someone else), so I can not make more pictures.

Thanks in advance!

[mlespaul]

Okey dokes, what you got there is a nice kriegsmarine 0,7 M EM (refers to the optical length of the instrument) Entfernugsmesser (rangefinder). I've seen this one on a couple other sites and I've asked the owner to describe the viewing scales within, whether its a coincedental or stereoscopic type. I'm guessing its coincidental based on it's size, but there has to be some sort of scale or point markings when you look through it.

The plate reads:

"Heights correction knob:
First calculate the degree of height correction in the Em. by viewing agains a distant objective, then apply height correction in the Ber. (Em's) device for that distance.

Measurement:

Place the alignment marking (when viewing through the eyepiece) closely underneath, not beside, the alignment marking of the EM."

This tells me the viewing display requires the user to match one mark directly underneath another by the knob, (and thereby rotating the mirrors) to signify the correct angles of the mirrors inside the lens' assemblies are aligned to compute the distance/height.

Anyway, I've read descriptions of this one that it was part of the complement of equipment that was found on a Uboat. Based on this one's smaller size, its entirely possible, but it would be difficult to substantiate. Its possible this belonged to the stowed equipment on an S-boat, E-boat, or any number of smaller types of minesweeper or ship that had a ship's cannon of 37 mm or greater.

The crew would use this item to view a distant target (like a ship) that was to be attacked with a deck cannon. This item is calibrated against a predetermined distance. Then, when viewing the distant object , the optical properties of determining the distance to the target was calculated through triangulation based on the lenght of the EM (in this case 0.7 m), the angle or degree of view as adjusted by the user on the EM, and then back-calculate the distance as the third factor (x). "Finding" the distance, then , the user would call out the estimated distance to the deck gunner, who then adjusted his cannon sights to that marking on his sights and fired away.

If this were a coincedental EM (I think it is) the user would "match up" two "halves" of the viewable image until they were matched up, then the user knew that the viewing angle was accurate in order to determine the third numerical value of distance.

These 0,7s of course were limited in that because of their shorter length only so much accuracy of estimation was possible if a ship target were farther out. This one is also unique in that this one, like most Kriegsmarine optical items, had the objective lens' protected by flaps to seal out saltwater or moisture.

To answer your questions, yes it does appear to be complete in of itself, yet the full system would have the case, but then I see the serials do match and I do not know what's in that small "zum 07 Biro" case, unless its the illuminating bulb kit. One of the pics appears to have the illumination port connection, but can't be 100% sure. Confirm whats in that accessory box and you can get a better feel for the estimated value.

If it could be substantiated that it has a Uboat pedigree, the starting asking price can begin in the lower 1,000.00 USD, again, based on whats in the accessory box. If not, one can begin asking 700.00 USD, mostly due to the fact these smaller KM ones arent seen very often. In any case this would fetch quite a bit of interest by collectors, expect at least 5-6 bids.

[Skylighter]

Thank you"mlespaul" for the thorough explanation!

[Lexy]

Very interesting indeed, do you think these came in a box like this?

[Lexy]

..

[48RMC]

Hi,
very interesting topic I have the same Entfernungsmesser with the wooden box but it has has a synthetic label instead of letters hows been painting on the case. If you like I could place a pic but I need your help because I'm very clumsy in such thinks (pm). I read that you (mlespaul) have see a few times on internet these kind of range-finders, 0,7 biro. I have tried many times but without luck could you give me a link to one of these websites? It will be nice also if someone has a photo application taking during the war. I don't know why but I like Km optics and this part was unknown for me till now thanks boys

[mlespaul]

Lexy,

Yours is a bit different. Your EM is a binocular 0,7 Rf Kriegsmarine rangefinder, which I believe is the larger cousin to the 0,7 Biro.




The 0,7 Rf (Raumbild Fernrohr or Richtungsweiser-Fernrohr) was a stereoscopic rangefinder. I think the Biro is the smaller, more compact version. But I'm not completely 100% sure of the Biro's operation, just yet.

Our "Biro" I think, is a term applied to this model as it is smaller. "Biro" is a universally known term for ballpoint pen, but also has origins in old German or Hungarian dialects for "judge", in this case judging distances. The Nazis often combined words and phrase when applying terms and names to equipment, so this might also be the case. "Biro" is probably something used to differentiate it, again, from its' more complex cousin the 0,7 Rf even though they shared the same Base length.

[48RMC]

Lexy,

Yours is a bit different. Your EM is a binocular 0,7 Rf Kriegsmarine rangefinder, which I believe is the larger cousin to the 0,7 Biro (absolutely not the Biro is the big brother from the RF range-finder in all parts).


it's obvious both are range-finders but the biro is a "totally" other device then the Rf range-finder. The biro has no ocular concerning to the Rf range-finder. I have "no idea how to use" this biro range-finder but given it's weight and his click system in comparing with the Rf you have to think about a fixed point with another device to make measurements possible. So there must be a technical part that belongs to the biro range-finder to make it useful. But we have no idea which part it was so i hope that someone has a application photo. I have the wooden box for the biro and the range-finder as well but i have no notion how to place a picture on this forum.

[48RMC]

compering the rf range finder with the biro

[48RMC]

pic 2

[48RMC]

click system and the knob how knows maybe to connect with another technical optic device?????


Hé Eric bedankt voor je hulp zonder jou had dit niet gelukt,
groetjes Ut het zonnige maar ooooo zo kouwe Walcheren

[48RMC]

You have a wonderful complete Rf range-finder with all the necessary accessories Mlespaul

[48RMC]

[QUOTE=48RMC;3729110]Hi,
.......

[mlespaul]

hee, hee, it's not my set, but belongs to another collector !


Wow, great pictures! I had no idea the Biro was that much larger than the Rf. (I figured it must be smaller!)

I think you're right, the Biro must have been an accessory or component that belonged to a system, perhaps integrated into a rangefinding system in a bunker overlook in a coastal installation or even mounted as part of something in a ship.

You said there's no place to place your eye to look through the Biro, correct? Only that connection "plug", right?

[48RMC]

hee, hee, it's not my set, but belongs to another collector !
Ohhhh sorry that was not obvious for me but anyway a nice complete Rf rangefinder i like this state

Wow, great pictures! I had no idea the Biro was that much larger than the Rf. (I figured it must be smaller!)
That's why i have put a photo in this thread to make a comparison

I think you're right, the Biro must have been an accessory or component that belonged to a system, perhaps integrated into a rangefinding system in a bunker overlook in a coastal installation or even mounted as part of something in a ship.
Yes could well be because a bunker is dark place so the battery light is not a luxury at all. But on board on a ship is also possible there are dark place as well but maybe i'm wrong
You said there's no place to place your eye to look through the Biro, correct? Only that connection "plug", right?

If you mean that the plug which i point out with the word knob then we talk about the same thing but this part of the range finder can not be used for visual purposal. Maybe this part was the connection with the computer or the ocular device???

It's still a big enigma this biro 0,7 range finder