FM-2n and Diopter correction

[Frank Fremerey]

Aerobat's FM-2n I bought is still in the post but it already
got me thinking: How will I shoot it?

I bought some prepaid non reusable chemical sensors to do some
whacky experimental stuff with them. I also have some very decent
MF glass to draw light structures with photons. Plus a lot of not so decent...

Yet it just crossed my mind that my biological light sensors
are seriously challenged and the FM-2 might not have any means
to compensate for that but insanely expensive screw in lenses.

Help! Please...

[Bjørn Rørslett]

You might need diopter lenses for the ocular, Frank. If I recall correctly, the finder is set for -1 dioptri which is the Japanese norm. It has no further means of direct adjustment.

I just checked with a pristine FM2 sitting in my cupboard and I definitively need my reading glasses to see anything in the otherwise nice, bright finder. Do put an eyecup on the ocular to save your spectacles from being scratched.

[charlie]

Provia 400, so sad to see that one go.

[Frank Fremerey]

I am +2.5 so do I need a +3.5 correction lens then? Or do I need a screw in rubber plus reading glasses?

screwin'rubber ..... hahahaha

[Bjørn Rørslett]

Try without glasses first.

The reason they put in -1 as a standard is the need for seeing both finder information, and ground-glass image, reasonably sharp at the same time. Thus the inherent focus of the system is at 1 m, explaining the -1 dioptre setting. People have different ability to accommodate their eye sight thus a practice test is recommended before you commence the screwing-in of any attachment lens(es).

[Frank Fremerey]

And where do I get the rubber and the correctional glass elements ... just in case ...

[Bjørn Rørslett]

Rubber eye cup is standard Nikon accessory - ask your dealer. They should also be able to supply the dioptre attachments for the ocular.

[pluton]

Bjørn's advice to try in person is highly advised, because Nikon has a peculiar naming convention for their eyepiece diopters.  The diopters are named for the net camera finder  +  diopter value, not for the diopter value of the lens by itself.  If you want to shoot using your spectacles, by all means test while wearing them.

[Matthew Currie]

I'd definitely try it out first.  I am comfortable reading at 2.5 to 3.5,  but find a +1 diopter about right on a Nikon viewfinder.  Stacking two +1's on top of each other is too much.  At one point I ordered a +1 for my F3HP, and KEH accidentally included a +3 along with it, and it's totally unusable.

Figure what diopter you'd need to see a computer screen from a meter away, and that's pretty close to what you need in a correction lens.

I've gotten a couple of these things used from KEH.com.  Some of the newer diopter rings have a rubber rim that's a bit heavier than it used to be.  Nikon's own chart is confusing.  There are actually only two thread sizes made - one for the earlier Nikon Photomics and Nikkormats, through the non-HP F3, and one for the HP F3 and subsequent models with threaded eyepieces.  Any other differences are in ring design, not threads.

[Frank Fremerey]

Confusing. I prefer NOT to wear glasses because I cannot see anything with them except in the very near field

Computer Screen 1 Meter is roughly +1.5 to +2.0

[pluton]

Confusing. I prefer NOT to wear glasses because I cannot see anything with them except in the very near field

Computer Screen 1 Meter is roughly +1.5 to +2.0

In theory, the Nikon "0" diopter or the Nikon "1" diopter should accommodate your vision.

[Eddie Draaisma]

My eyesight is still good at large distances, but not at the 1m virtual finder distance (-1 diopter) anymore. For the old Nikons without built-in diopter adjustment (including a FM-2n) I bought +1 diopter screw-in eyepieces from EBay. Problem solved. Note that the diopters for the Fujifilm X-Pro1 (still available as new) will fit the FM-2n.

[abergon]

There is also the nuclear option: laser eye surgery. I am writing from personal experience.

[Frank Fremerey]

Nono. It is reading glasses. And it is a non laserable aneurism. Laser simply is no solution in my case.

But. I ordered a +1 Nikon Diopter brand new from Japan at 20 Euros incl. Shipping.

I studied the Nikon documentation on that topic on service nikoneurope eu

hope all will be worth the effort in the end.

[Eddie Draaisma]

Nono. It is reading glasses. And it is a non laserable aneurism. Laser simply is no solution in my case.

But. I ordered a +1 Nikon Diopter brand new from Japan at 20 Euros incl. Shipping.

I studied the Nikon documentation on that topic on service nikoneurope eu

hope all will be worth the effort in the end.

The +1 should work for you if your eyesight is (still) good at infinity.

You will find out that on the FM2 the 35/1.4Ais gives the impression of a much bigger lens. No (MD11/MD12) motordrive??