top mounted rangefinder calibration

[adwb]

If this enquiry is posted in the wrong place please accept my apology and move it.
I need advice on how to adjust a typical look through double image range finder.
I have seen instructions that say look at a distant object with the dial set at infinity. Adjust the two images to over lap and that’s it. I have 4 different ones and if I try this then check near object of a known measured distance the readings are way out. How far away must the distant object be?
is there some trick to this ?
I hope someone can help with this "old technology" question
Regards Alistair

 

[ChrisN]

Welcome to the forum!

The necessary adjustments will be different from one camera to the next, as some have very simple mechanisms while others are more complex. What cameras do you have?

 

[MartinP]

I think the OP was talking about one of the rangefinders that sits on top of the camera in the accessory shoe, rather than being built-in.

Details for adjustment will vary from model to model of course, but many people have used either the moon or an object on the horizon as an infinity reference.

 

[Roger Hicks]

They were often quite cheaply made and are usually buggers to adjust. I use the horizon, or anything over about 300m away -- and a lot of the time they don't work anyway. I have a couple somewhere and neither is reliable. Practice guesswork. The army tricks I was taught as a cadet are (1) how many 6-foot soldiers could be laid end to end in the distance available -- no crude jokes please -- and (b) how many cricket pitches is it from here to there. Presumably non-cricket-playing nations can think of an equivalent measure. Anything less than 6 foot can be guessed by reference to an arm's length from the shoulder (about 30 inches).

Cheers,

R.

 

[payasam]

Alistair, the moon is an excellent distant object. I don't know if anyone can help unless you say which kind of R/F you mean.