Non pocket sized rangefinder

[eldon]

If anybody is after such a rangefinder have a look at this,

 

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?Vie...A:IT&ih=003

 

Old but made by zeiss. At 28 kilos and 5' long might be limited in some applications.

[eldon]

Plenty of views and no comments? or are you all secret bidders/buyers.

 

How do these things work then, is it a case of focusing the target and the parallax is what is giving you the distance measurement?

 

Looks a similar thing to another one I looked at on the net, think it was a Barr and stroud and these apparently are sought after so I'm told.

[casts_by_fly]

you look through the central eye piece and there are two images reflected through the device in mirrors. You adjust the dial until the images line up. When they line up you read the dial for yardage.

 

The idea is that the distance between lenses (on the ends) is fixed. You set the angles between the eyepieces and the central bar by focusing the two images together. Trigonometry will tell you the rest.

 

distance to target = length of pipe/2 * tangent of the angle between the outer eye and the central pipe.

 

thanks,

rick

[Ronin]

Huge collectors market for these things.

 

They are still used in the states - Barr and Stroud (Glasgow) and Wild are well known names for optical rangefinders - believe they are very accurate too, although weight is against you all the time.

 

I'm pretty sure that the image you see through these is upside down too, which may cause a bit of confusion.....

 

Would love to get a WW11 Barr and Stroud, just for the history.