Do I need a diopter?

[Shaocaholica]

I just got my R3A and I've just realised that the viewfinder doesn't do anything for my nearsightedness like my SLRs. So, would it be possible to use my RF without glasses and still resolve far away subjects with the aid of a diopter? My eyesight isn't that bad at all but it would help me tremendously to focus with sharp images rather than blurry ones.

Also, how do I know what power diopter I need? Is it based on my glasses pescription?

Edit: What's the correction value for the R3A without any diopters?

Edit2: If anyone thinks they could use a -3.0(-2.0 actual) diopter for their R4x/R3x/R2x, let me know.

 

[payasam]

Your glasses prescription can only be a guide. For my SLRs I needed rather less positive strength than my reading prescription. My answer was to go to my optician's and try out lenses of different powers before having the correct one fitted into a special pair of spectacles (the other eye being set to normal reading strength, for the small lettering on bodies and lenses).

With correction, you should be able to clearly see (through the finder) objects a yard and a half away. Since you are myopic, you must work the other way from me. I do not know if you are presbyopic as I am.

The correction attachments ("diopters") that Canon made for the FD series were marked with the "wrong" strengths: the one marked +3.0, for instance, was in optical terms +4.0. This was to take into account the -1.0 to which most or all finders are set. It is possible that all manufacturers follow this practice. Your R3A's manual should say.

After I had cataract surgery I found that I needed only +0.25 D, which is close enough to nothing. This is by the by.

 

[Shaocaholica]

My R3A was bought used and didn't have a manual 🙁 Are the manuals avaliable online? I've pretty much figured out all the workings but maybe I'm missing something really obscure.

Anyway, it seems that the Nikon diopters which fit the bessa are off by -1.0 to account for the -1.0 of the Nikon camera VF. I think I will probably want the -2.0 or -3.0 Nikon diopter. If my eyes require a -1.0 correction value but my camera is -2.0 or -3.0, what would that look like to me?

 

[payasam]

If your ordinary prescription is -1, it seems to me that you should need no correction when you use the camera without your glasses. You could try looking through the finder while wearing someone's +1 or so glasses. An experienced optician would be the right person to ask. Everything depends on whether or not you are old enough to need different powers for distance and for reading.

If you cannot find a manual for your camera on line, you might like to write to Stephen Gandy at the address you will find on http://www.cameraquest.com. He should be able to send you a photocopy at least. Come to think of it, he might be able to help with your diopter question as well.

 

[Shaocaholica]

Well, I wear prescription glasses pretty much for comfort as I can resolve things fine to get by. The only exception is reading far away signs at night while driving on the highway.

The thing is, I can't really see fine detail at distance and looking through the VF of my R3A looks exactly the same as not wearing glasses and the image in the RF patch is blurry for far away subjects and I'm having a hard time lining up the images precisely. It looks fine when I wear my glasses but then I can't see the framelines.

 

[Shaocaholica]

Just picked up a -2 new Nikon diopter and things look great!

 

[payasam]

Minus two? You must be young, then. Good: more time to use the camera well.

 

[Shaocaholica]

Minus two? You must be young, then. Good: more time to use the camera well.

If I'm not mistaken, -2.0 Nikon is only -1.0 which is perfect for my myoptic eyes. Still, without the -1.0 correction, it bothers me that I can't see the patch clearly for subjects far away.

 

[payasam]

You're almost certainly right that the lens marked -2.0 is optically -1.0. Now that you have the proper correction, no need to work without it. Myopic or hypermetropic or presbyopic eyes can usually be dealt with easily enough.

 

[adam_ball]

Hi

I've been trying to work out the right diopter for the Bessa R2. My Nikon D50 has a built in diopter with a range extending to -1.6 which is where I leave it when I'm not wearing glasses so I guess a -2 diopter attachment would be good on the Bessa. I've found this chart http://www.nikonusa.com/fileuploads/pdfs/EP_CompChart.pdf
which indicates that Nikon Diopter -2.0 ref no 2945 is the one for me. About $12 or £12 either side of the pond regardless of current exchange rates!

I assume this slips neatly over the existing eyepiece...

Adam

 

[payasam]

It appears that the FM-10 was made by Cosina, which is why its diopters (and possibly other attachments) fit the CV Bessas. Shaocaholica will know.

 

[Shaocaholica]

The R3A takes circular nikon diopters and I think the R2 takes the rectangular ones.

 

[Shaocaholica]

Ok, so I got both a -2.0(-1.0 actual) and -3.0(-2.0 actual) Nikon diopters for my R3A. Seems like the -2.0(-1.0 actual) works out best for my very minute near vision. The -3.0(-2.0 actual) still works but takes my eyes about 1 second to adjust to it. If anyone thinks they could use a -3.0(-2.0 actual) diopter for their R4x/R3x/R2x, let me know.

 

[Santafecino]

Whew--thank you for that.

Now, does anyone know how to attach a diopter lens to an accessory finder? I have a CV 35mm finder that is a tiny bit too "minus" for my right eye.

 

[Shaocaholica]

Whew--thank you for that.

Now, does anyone know how to attach a diopter lens to an accessory finder? I have a CV 35mm finder that is a tiny bit too "minus" for my right eye.

You might want to ask S. Gandy. Now I'm even more turned off by accessory finders if they don't take any form of diopter 🙁