Rangefinder adjuster for what and how to stop it

[horacekenneth]

Can anybody tell me what this adjuster lever is for? I can tell it's changing my rangefinder but it just goes from crisp to blurry. It used to be firm in position but it's come loose to the point where it basically swings around. How can I tighten it down or fix it in place altogether?

 

[Peltigera]

That lever has nothing to do with the rangefinder. It adjusts a dioptre lens in the viewfinder so that you can use the camera without wearing your glasses.

 

[horacekenneth]

Strange, it's definitely affecting my rangefinder. and no effect on the viewfinder side

 

[mshchem]

Strange, it's definitely affecting my rangefinder. and no effect on the viewfinder side

You are correct, it adjusts the focus of the rangefinder, screw mount Leicas have a magnifier on the rangefinder, so it adjusts a diopter for the rangefinder magnifier. Doesn't effect the viewfinder .

 

[AgX]

With an SLR one has to focus the eyepiece onto the ground screen. Aside of daily fluctuation one only has to adjust once
With rangefinder cameras one better adjusts the eyepiece for the range at which one is just focusing at. Thus a variable eyepiece even for only the same photographer is more benefitial than at an SLR.

But we all know that adjustable eyepieces were rare at rangefinder cameras and nonexistant with SLRs.

 

[mshchem]

With an SLR one has to focus the eyepiece onto the ground screen. Aside of daily fluctuation one only has to adjust once
With rangefinder cameras one better adjusts the eyepiece for the range at which one is just focusing at. Thus a variable eyepiece even for only the same photographer is more benefitial than at an SLR.

But we all know that adjustable eyepieces were rare at rangefinder cameras and nonexistant with SLRs.

I have a early Leica III model F, you can see the magnifier move in and out . Makes a huge difference in clarity

 

[horacekenneth]

Any help with fixing it in place or opening it up and adjusting it so it stops swinging in and out? It used to be quite firm and now it flops back and forth

 

[John Koehrer]

I'll catch hell for this but the collar that needs to be tightened is under the rewind knob. The lever has a pin that drops into a hole
beneath it.
The hard part is tightening the nut. The nut is ~1mm thick, maybe a bit less and has very fine threads. If the nut's
still in place & just loose you may be able to snug it down using the tip of a straight pin. If it's come off the threads there's
a really good chance to cross thread it.