advice needed on viewfinder diopter lens

[macrorie]

Much of the time I shoot with a Nikon F2A and FM2n, and I have recently had trouble with the viewfinder focus. Although I am really nearsighted, I suspect this problem is because of increasing middle-aged close vision problems, and I wear bifocals to correct the problem. To improve my ability to focus with these cameras should I get -1 or +1 diopter viewfinder correction lenses? The problem is not severe, just enough to add some uncertaintly in focusing.

 

[Nicholas Lindan]

I have the same problem. I use a +1 lens: this puts the focusing screen at infinity, or 0 diopters, where my far vision is well corrected. Nikon viewfinders are normally set to a 1 meter focus, or -1 diopters, with the standard viewfinder lens.

In a hopeless effort to simplify things, Nikon confuses the issue by labeling the +1 lens as '0'.

http://www.bhphotovideo.com/c/product/37306-REG/Nikon_2930_0_Diopter_for_FM2_FE2_FA.html

Don't forget that with your glasses on you are no longer nearsighted but are now farsighted. I had to argue with the camera clerk on this one - she insisted I needed a negative diopter lens because I was nearsighted.

 

[macrorie]

Nicholas, thank you, that is exactly the information that I needed.

 

[rolleiman]

I've also experience the problem of Nikon classifying the +1 as an 0. A word of warning about these diopter lenses....in my experience they have a nasty habit of unscrewing themselves and dropping off from the viewfinder while you're carrying your camera around...possibly as a result of vibration build up through carrying them in a car.......Witness the number of s/h Nikon FM2's on sale without the neutral screw in lens!....Be warned!

 

[Nicholas Lindan]

Witness the number of s/h Nikon FM2's on sale without the neutral screw in lens!

I've lost them when having to remove them to mount a right-angle viewer. There is a large collection of small camera bits in the back lawn of the house.

 

[E. von Hoegh]

By some miracle, the neutral lens is still present on my Nikkormat FtN.

 

[Neanderman]

Their numbering is VERY confusing. Knowing that I wear +2 glasses to read and also knowing that the viewfinders are set to -1, I bought a +3, thinking that would get me to a +2. But the +3 is unusable! It is WAY too strong.

Ed

 

[mablo]

I found out some time ago that Voigtlander Bessa rangefinder correction diopters can be used with manual Nikon bodies. They can be found from -3 to +3.

 

[vpwphoto]

I used to put a drop of clear nail polish on the threads before I screwed the one on I wanted. It stayed put without being permanent.

 

[macrorie]

Yesterday I received a +1 diopter from KEH that I thought would fit only my FM2N, and to my surprise, it fits both the FM2N and the F2A. And it works perfectly: I can focus with confidence with my 35mm SLRs once again. Thanks to all who provided advice: I will be careful to avoid losing the diopter (especially since I discovered that these little lenses are not that common on the used market, and the new ones cost $27).

 

[E. von Hoegh]

It will fit most any Nikon from the F onward. Use the fingernailpolish trick, or if you wish to go "retro" use a tiny dab of boiled linseed oil.

 

[Neanderman]

...if you wish to go "retro" use a tiny dab of boiled linseed oil.

Or shellac, which is very easily dissolved with alcohol.

Ed

 

[E. von Hoegh]

Or shellac, which is very easily dissolved with alcohol.

Ed

Personally, I like safety wire. Locking tabs are good, too.