Eye correction lens replica for Nikon F, F2 and all other cameras with M 19 x 0.75 mm thread.

[Alpsman]

Since these eye correction lenses are a bit difficult to find, at least usually not in the right strength, and they often charge high prices for them, I decided to recreate them.The ring itself is a simple turned part. My thought was to use the lenses from those dirt cheap reading glasses. So I took the measurements of my existing correction lens, started the lathe and turned a test sample. The trickiest thing was cutting the 1.5 mm long M 19 thread with a pitch of 0.75 mm.


Test the thread with the viewfinder - it fits.


For my weak eyes I need a correction lens with +0.5 diopters for the camera. So I took one of those dirt-cheap glasses with a power of +0.5 diopters, stuck a paper template on it and sawed it out with the Dremel and sanded it so that the lens could be easily pressed into the ring. If necessary, secure with 2 components of glue.




And - it works 🙂 The grid lines in the viewfinder can be seen clearly. I didn't want anything more.

 

[Retro-Grouch]

Nice work! Although, without ready access to a lathe, I would probably just empty my wallet for the thieves on eBay. A tip for those looking for a -1 diopter in this thread: Nikon never made one in that strength, but they were made for Bessas and the Zeiss ZI. I think I cleaned out the last of them from Mr. Gandy's stock a while ago, but it helps to know this if searching the internet for used ones.

 

[Alpsman]

If I didn't have a lathe in my "playroom", I would have to pay these prices too. But if you can't find a suitable lens, all the money is useless.
The lenses with +0.5, +1 or +2 in particular are practically impossible to find.
Except for those for the Nikon F3 HP viewfinder, but these have a 21 mm thread diameter :-(
But the main reason I was playing around was to find out whether you could use the lenses from these cheap glasses for a corrective lens.
And yes, it works 🙂

 

[Timmyjoe]

I've been doing this for years using grocery store bought reading glasses, what my sister and I call "cheaters". They work great. Had to build a special holder for the lathe to hold the curved surfaces of the lenses, but when you can get a pair of "cheaters" for $9.99 at the local Jewel/Osco, which gives you two diopters, it becomes a no-brainer.

Although I haven't tried machining the metal screw in ring, I just create the lenses and then press fit them or hold them with a bit of gaffers tape.

Best,
-Tim

 

[Alpsman]

As I mentioned above, not everybody have a lathe in his playroom.
But I can help you too.

If you have a 3D printer or know someone who does, or have the opportunity to have something 3D printed, or...

Here's the model for the corrective lens, free to download, of course.

Nikon Augenkorrekturlinse; Nikon eye piece correction lens by blechbude | Download free STL model | Printables.com

Download 3D printable STL models

www.printables.com

The description is actually included, but here's a brief summary:
The threaded ring is available with a depth of 2 mm, 3 mm, 4 mm, or 5 mm for the lens, depending on the correction and therefore the thickness of the lens required.
The thread is a M19 x 0,75, it fits also a Texas Leica for example and it works also (I've tested)
also ya can use it on my eye piece correction holder for the Nikon S2.
Cut out the lens yourself from one of those cheap reading glasses with plastic lenses and glue it in, or melt the edge with a hot screwdriver, knife tip, or something similar.

I wish you always a sharp eye & GFA: Dieter

PS: The edge is intentionally not provided with a chamfer to increase the grip when unscrewing ;-)