PentaxWorld - the World of Pentax Users!

Welcome, Guest. Please login or register.

Login with username, password and session length


 homemade diopter eyepiece

0 Members and 1 Guest are viewing this topic.

October 18, 2009, 05:22:24 AM
Read 13531 times

Dan Daniel

  • Guest
homemade diopter eyepiece
« on: October 18, 2009, 05:22:24 AM »
I've had good eyesight all of my life so I am not used to wearing glasses. My close vision has gotten worse over the last few years, though, and reading glasses are now going everywhere with me. The K10 has a diopter built in to the eyepiece. But I've been using older film cameras without this and have been having problems seeing information and focusing.

The other day I figured I'd try wearing low-powered reading glasses while looking through the viewfinder. I went to the drugstore and tried various ones until I found a power that worked- +1.25- and a style that worked- all plastic frame, no projecting feet to dig into my nose or eye socket.

The problem was that I had to keep taking the glasses on and off, pushing them up tight for using the camera and pulling them away at all other times. Maybe those who have worn glasses for decades do these kinds of things easily but not me.

A while ago I bought an eyecup for the 'M' series Pentax cameras. The dealer's name on eBay is jruss71731. The part itself is-

The eye cup has 4 main parts: the main mount body, a glass plate covering the opening, a rubber eye cup, and a retaining ring holding both the glass and eye cup in place.

I decided to see if I could get the lens from the reading glasses into this eyepiece, replacing the glass with a diopter lens. And it worked!

I don't have a photo of the parts without the new lens installed, but pretend the lens installed is simply flat glass and this is how things start-

Retaining ring removed-

All the pieces, plus new lens pressed into place-

I used the original glass circle and a Sharpie to mark the reading glass lens (this mark was off-center, so I used the other lens; alcohol would remove the marker easily). I used a Dremel with a cut-off wheel to trim away the excess and then used the same wheel as a 'disk sander' to do the final shaping and adjustment until the lens pressed into place-

I ended up with a press fit, but did apply a little white glue along the top and bottom edges for security (no super glue! it will fog the plastic). Some day I will probably pop the lens out and take a black marker to the rim of the lens-

Back view-

This is the diopter installed on a Pentax MX-

And a side view showing the amount of projection-

Now this does increase your eye's distance from the viewfinder. I cannot see the full screen as easily as I can without the eyepiece, but I do not have black corners; it just takes a bit more scanning, which on the huge MX screen is already needed.

But I can read the internal displays and I can focus with confidence. Well worth it to me.

The rubber cup part was keeping my eye too far away from the viewfinder before the modification. With the new lens installed, the retaining ring doesn't have enough threads to grab, so you would need to do some gluing or modifications if yo u wanted to have the rubber cup as well as the diopter lens.

On film cameras, this eyepiece, as delivered or as modified, does block the back door so it needs to be slid up to load film.

I have tried this same eyepiece on a K10d and it fit fine. The K10d diopter works well for me, but I guess if I needed an extra push, it would be useful.

October 18, 2009, 05:53:32 AM
Reply #1


  • Guest
Re: homemade diopter eyepiece
« Reply #1 on: October 18, 2009, 05:53:32 AM »
Now this is an excellent project. Well executed and professional looking. Where there is a need and will, there will be a way.

Thanks for posting this. With all the dollar store reading glasses out there this could be a cost effective solution for many members.


October 18, 2009, 08:01:33 AM
Reply #2

Offline Mike Pearson

  • Emeritus Staff
  • *

  • 5,345

    • Mike Pearson's photos
Re: homemade diopter eyepiece
« Reply #2 on: October 18, 2009, 08:01:33 AM »
Superb and ingenious job - thanks for sharing  8)

K30D, K100D, MZ7, MZ6, DA 18-135 f/3.5-5.6 ED AL[IF] DC WR, FA 28-105 AL IF , FA 50 f/1.4, DA 35 f/2.8 Limited, DA 70 f/2.4 Limited, DA 16-45 ED, DA L 18-55mm, DA 50-200 ED, DA 55-300mm F4-5.8 ED, Pentax AF-360FGZ, AF-540FGZ.[/

October 27, 2009, 08:34:07 AM
Reply #3


  • Guest
Re: homemade diopter eyepiece
« Reply #3 on: October 27, 2009, 08:34:07 AM »
Very nice. When are you going into mass production? put me down for 1.


October 27, 2009, 09:19:07 AM
Reply #4

broken calsan

  • Guest
Re: homemade diopter eyepiece
« Reply #4 on: October 27, 2009, 09:19:07 AM »
Very well done.  It's also nice that your solution kept the good looks of the original camera.

October 23, 2011, 03:00:08 AM
Reply #5

Offline Pacerr

  • Administrator
  • *

  • 1,535

Re: homemade diopter eyepiece
« Reply #5 on: October 23, 2011, 03:00:08 AM »
Well done, Dan.

I used the same solution (for the same reason) on my MX some time ago except that I had an eye-piece from a defunct A3000 to use as a frame. Cutting a "square" lens is arguably easier than making a round one; although, if a diamond tipped hole-saw fits the adapter that works too - if you go slow in a drill press and take care not to melt the plastic lens.

H2  -  I'm not gettin' any smarter in my old age -- I'm just finally beginnin' to run out of really stupid things to do. Doesn't mean I'm not tryin' though.

No trees were killed or injured in the sending of this email, but billions of electrons were really, really agitated.

October 23, 2011, 05:36:03 AM
Reply #6

Ron Kruger

  • Guest
Re: homemade diopter eyepiece
« Reply #6 on: October 23, 2011, 05:36:03 AM »
Wonderful idea and execution.