“optical range finding”
Cool - thanks! I had an old optical range finder where you would look at something (a tree) and see two of them (stereo) and turn the dials until you saw just one, and then look at the distance on the dial.
Was the optical range finding in WWI a similar thing?
Yes they work just like the rangefinders on old cameras except their base is far wider giving them greater accuracy.
I saw one at a gun show not too long ago. It was maybe 4 feet between lenses and had a nice clear image. I have no idea how much they are worth but this guy wanted about $500 for his.
I didn’t have $500 so I tried trading him all kind of things, giving him better than $500 value but I guess he wanted cash.
I have read that they can be very accurate.