How to focus a focusing loupe?

[jcc]

I've been using a Fuji Professional 4x loupe, but it's gone somewhere into abyssal storage, so I'm borrowing a friend's Rodenstock aspheric 4x loupe. I wear glasses, so looking through the loupe does not render a sharp image. Is there a way to focus the Rodenstock loupe? I was able to do it adjust focus with the Fuji loupe, but can't figure out how it's done with the Rodenstock.

Just to be clear, I'm asking about how to change the focus of the Rodenstock loupe, not focus of the camera. Thanks!

 

[ic-racer]

Twisting it doesn't do anything? It should go from +0.5 diopters to -2.5 diopters when you twist it.

 

[AgX]

Have you tried it with the eye-cup rim downfolded?

 

[jcc]

Twisting it doesn't do anything? It should go from +0.5 diopters to -2.5 diopters when you twist it.

Twisting the only threaded part disassembles the lens from loupe. There's no depth control on the Rodenstock (which the Fuji has) that I can see.

 

[jcc]

Have you tried it with the eye-cup rim downfolded?

I tried it; along with various amounts and shapes of squinting (seriously, a good couple minutes worth). No luck.

 

[AgX]

Most probably someone has twisted the focusung thread to arrest.