Eyepiece correction lens diopters

blumesan

Well-Known Member
NOTE TO ALL CONTAX SLR OWNERS WITH AGEING EYES:

Most Contax bodies do not have built-in correction diopters. The solution for RTS I & II, 139Q, 137MD & MA, 159 and 167 is to obtain a corrective lens which screws into a slip-on eyecup. The eyecups themselves (either Contax or Yashica) are generally available in the used market. However I have found that the corrective lenses, especially those with positive diopter correction, are very hard to find. These are the corrections required by senior citizens suffering from presbyopia (ageing eyes).

Purely by chance (out of desparation) I found that a Nikon “eyepiece correction lens” designed to fit the Nikon series FA, FM & FE series cameras is a perfect fit for the Contax/Yashica eyecup. They are easily available in a wide range of corrections on e-bay and at other sources.

The other advantage of this solution is that you only need one eyecup-lens set and you can easily transfer it between camera bodies.

Try it, you’ll like it.

Mike Blume
 

bobbl46

Well-Known Member
Mike ..... If I could read you right ..... I'd say this was excellent information ..... just hold on while I find my glasses! Darn'it ..... I can see now!

"Drop in" is the phrase I think Mike is looking for! The Contax correction lenses "drop in" to the eyecup once you have unscrewed the retaining ring.

Well done, Mike .... any info of this nature is good info .... it's not a topic frequently discussed!

One thing to emphasise is that Contax did produce its own range of diopter lenses to fit the cameras you mentioned ...... I agree that they may be hard to find. But .... they can be found, with patience.

I think it is significant that you say that there is an alternative source from the mid-era F Nikon series ..... and that they are compatible.

I wonder if the millimeter(s) difference in the separation of the Nikon correction lens in its Nikon holder and ....... the Nikon correction lens in the Contax holder is significant in terms of the effectiveness for different viewers.

I agree that it is well worth experimenting with these alternatives (provided it doesn't cost you too much) and that "if it works" then it was well worth it!

More experimentation like Mike's should be encouraged ..... purely on the grounds of expanding the usability of Contax/Yashica equipment.

Cheers, Kyocera Kid.
 

blumesan

Well-Known Member
Hi Bob-
Good to hear from you.

No "drop in" was not the phrase I was looking for.
The original Contax/Yashica diopter lenses drop into the eyecup and are secured by the retaining ring. The Nikon lenses are provided in a mount having the exact same dimensions and thread size as the retaining ring, so they are "screwed in".

As for any small difference in the "separation of the correction lens", it is insignificant in terms of absolute distance. Also considering the fact that these lenses are supplied in whole diopter (=/- 1, 2, 3 etc.) while the average individual's "perfect" correction will seldom be such a whole number (e.g. +0.75, or -1.25). Close is good enough, or at least a whole lot better than no correction.

While Contax/yashica correction lenses can be found on the used market, most of them are negative corrections because that is what more people require. Positive corrections are mostly for us old folks, and either Contax didn't make as many of them, or their owners have taken them along to that great darkroom in the sky.

As for cost, the Nikon eyepiece correction lenses can be had for between $16 - $18 on e-bay.

Regards,
Mike.
 

bobbl46

Well-Known Member
Sorry Mike .... when I read your first paragraph, I thought you meant that the C/Y ones screw in!

I can see now that you know that they don't.

Actually, your information that the Nikon correction lenses screw directly into the C/Y eyepiece was unknown to me ..... and is excellent information at that.

Cheers, Kyocera Kid.
 

blumesan

Well-Known Member
ADDENDUM to my earlier post concerning the use of Nikon corrective diopter lenses in Yashica/Contax eyecups.

I have just learned that Y/C eyecups come in (at least) two variants, only one of which will accept the Nikon diopter lens. The “correct” type of eyecup can be distinguished by carefully measuring the outside diameter of the male thread on the retaining ring. If it measures 18.85mm, the threads are identical to those on the Nikon diopter lens. The second variant that I have come across has a retaining ring with an outside thread diameter of 19.80mm, which is incompatible with the Nikon diopters.

Mike Blume
 

jsmisc

Well-Known Member
Hello Mike,
Thanks for that. Am I correct that that Nikon lenses do not work with the newer oblong type Contax fittings like my Aria but only the round ones? I just wondered if Nikon might now have gone oblong also.
John
 

blumesan

Well-Known Member
>Hi John, Y/C eyepieces will fit the Aria. You must remove the rectangular eyecup that comes with the Aria and simply replace it with the old style round eyecup. The caveat is that the old eyecup must be one whose retaining ring measures 18.85mm (outside diameter of the threads). The Nikon diopter will then screw right into the eyecup replacing the retaining ring.

If you cannot find the correct Y/C eyecup, you can make do with the larger variant (19.8mm diam. thread on the retaining ring). You would have to secure the Nikon diopter in place with a drop of epoxy or some such jury-rig. It's a bit drastic, but if you hate looking thru the viewfinder with your eyeglasses on it's a solution.

I had purchased a rectangular diopter correction lens for my Aria before I made this discovery, but I have checked it out and it works just fine for the Aria and my 139Q. I am reasonably sure it will work with most if not all of the Contax SLRs.

Regards, Mike.
 

jsmisc

Well-Known Member
Hi Mike,
Thanks for that. That's very interesting news. I shall definitely consider it for my Aria. I much prefer not to wear glasses when focusing on something critical like a close up.
Best wishes,
John
 

blumesan

Well-Known Member
FOLLOW-UP using Nikon viewfinder accessories:

A right angle finder is a very handy gadget to have. The last one for Contax sold on eBay for over $100. A bit steep. But wait, there's more.
Nikon right angle finders made for the FM, FE series cameras have the same thread as the Nikon correction (diopter) lenses. So they too will fit into the Y/C eyecup threads, providing you have the right variant of the Y/C eyecup. See above posts. They can be had on eBay for a lot less than the "genuine" Contax accessory.

Caveat: some of the earliest Nikon right angle finders reverse the image left to right. Nikon models DR-2 and DR-3 present a correct image.

Good luck,
Mike Blume
 

jsmisc

Well-Known Member
Thanks again Mike. I haven't got a right angle finder and have often thought of acquiring one.
Cheers,
John
 
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