Diopter Correction on NC-2 Prism

[tenny66]

I have an old NC-2 prism and I would like to switch out the eyepiece lens for a +3 diopter correction lens, so that I can focus w/o spectacles. I have located a lens, product number 52175, but I can't confirm that this is the correct lens. Does anyone know if this will fit? Do all Hassy prisms take the same size (24.5 mm) correction lenses?

Also, I guessed at an eyepiece to focusing screen distance of 30mm/2.75 inches. Does this seem right?

Tim

 

[Victorh]

Hello Tim,

The partnumber you quoted for the correction lens is correct.
Please note the lens itself is not marked.
Unless you bought this lens new in box there is a chance you got the original lens with 0 diopter that was put back by the first user.
No use to measure the lens on its own because it will give a reading not corresponding with the nominal value.

That switch happens quite often with focusing screens.

Not all prisms take the same correction lenses.
The part number you quoted is right for all 45° prisms except the later PM(E) 45.



Vic.