Diopter dilemma ...

[LEGEND]

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Hallo to everybody

As the title of this thread say I have dilemma if should I go for one diopter, another one or no diopter at all.

My camera is Leica M9 Monochrom that has 0,68x viewfinder magnification and already in build -0,5D diopter.

In my case I have -0,75D and astigmatism on my left eye that is also a dominant one wich I use for focusing.
The right eye is -1D, also with astigmatism. I have prescription glasses for both eyes at -1D and correction 
for astigmatism. Actually I don't wear them almost never because they irritate me very much and after a wile I put them
off. Focusing rangefinder of my MM is big no go as I tried and it did't work for me. 

Now, my astigmatism aside I noticed that the in build diopter in my MM viewfinder with -0,5D  strength still make a little 
bit of difference. I tested this many times and I concluded that my vision is better when I look through the viewfinder.
Even when the viewfinder magnification of my MM is only 0,68x and that this make field of view smaller.

Now, the dilemma...

I have opportunity to buy two Leica diopters for my MM,  -1D and -1,5D ...
-1D is 50 Euro  and  -1,5D for 80 Euro.  They are both used and have no original packaging but are in very good condition.

I know that if I put -1D diopter in the viewfinder that already has one in build of -0,5D strength then that will give me again -0,5D...
So I se no improvement there, only that the field of view will get smaller on the viewfinder with 0,68x magnification.
The diopter with -1,5D strength will then give me -1D and that is something like my prescription are but with no correction for the astigmatism
that I have. Not sure if my math is correct here... 

I tried glasses from my friends that are -1D but with no astigmatism correction and noticed that they make my vision better. 
The thing is that if I go for one diopter of -1D that will make no difference in viewfinder, and if I go for the second option of -1,5D that can help 
like the glasses that I try... Both of them in each case make field of view smaller in the viewfinder of my MM...

I am not sure if the -1,5D diopter help enough to justify smaller field of view because it already in build -0,5D diopter give me small improvement. 
I am not eager to lose 0,68x viewfinder magnification that is already small enough.  I had Leica M11 and the difference of field of view is enormous. 

Please help because I don't want to miss opportunity for purchase of one of two diopters.
But also I don't want to buy and then only to find out that they make little bit of difference or not at all.  

So, should I go for the diopter or not and which one?

Sorry for my bad English. It is not my native language. Perhaps next time I should try Chat GPT...

Nikola




 

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[jaapv]

1. The built-in -0.5 diopter is not for eye correction, it is in aid of accommodation of a perfect eyesight to 2m which is the virtual distance  of the viewfinder patch Just forget about it.

2. It is very hard to calculate the needed diopter from your prescription. It needs an optical expert.

3. The only practical way to determine which diopter you need is to visit your optometrist and use his trial lenses between your eye and the ocular. Choose the nearest value to the one that gives you the best vision. If  you are nearsighted you can attempt to use the throw-away glasses from your supermarket.

4. If you have astigmatism, you can use the above system, but when you turn the camera to portrait it will be worse. WalterLeica offers a solution.

So don't go buying diopters all over the place. First determine which  one you  need and then buy  one.

Don't confuse diopters with  magnifiers. Those are the ones that limit the angle of view and change the rangefinder base.  They are  given a value like 1.4x. They often need a different value diopter from the "naked" ocular

 

[LEGEND]

1 hour ago, jaapv said:

1. The built-in -0.5 diopter is not for eye correction, it is in aid of accommodation of a perfect eyesight to 2m which is the virtual distance  of the viewfinder. Just forget about it.

2. It is very hard to calculate the needed diopter from your prescription. It needs an optical expert.

3. The only practical way to determine which diopter you need is to visit your optometrist and use his trial lenses between your eye and the ocular. Choose the nearest value to the one that gives you the best vision. If  you are nearsighted you can attempt to use the throw-away glasses from your supermarket.

4. If you have astigmatism, you can use the above system, but when you turn the camera to portrait it will be worse. WalterLeica offers a solution.

So don't go buying diopters all over the place. First determine which  one you  need and then buy  one.

Don't confuse diopters with  magnifiers. Those are the ones that limit the angle of view and change the rangefinder base.  They are  given a value like 1.4x. They often need a different value diopter from the "naked" ocular

 

Thank you very much for your fast and informative response.

Every time I think about these diopters for my MM my head start to spin...
It seams that I got everything completely wrong and unnecessary complicate things for my self.
I will do as you recommended , just go to supermarket and try out some with my MM.
If one makes some a difference good, if not than I will stay with original set up...

One of my friends has Leica M11 and as I know he use a -1,5D diopter with the camera.
I know that this diopter doesn't fit in the viewfinder of my MM because it is larger diameter
but I can hold it between my eye and ocular to it try out. He is now traveling but will be back 
in few weeks. 

I think that I got spoiled from excellent EVF of my SL2-S. Like IMAX large, very bright, fast and also 
has variable diopter that I had set and forget. No eye fatigue or similar...

But Leica M9M rangefinder is something completely different. Until now I had almost never mis focused 
but as I age I also get paranoid about this...

[jaapv]

There are two types of diopter. The smaller ones for the m8/9 and film cameras and larger ones for the newer cameras. Make sure you get the right size. 

[jaapv]

And read the focusing post in the M FAQ

[LEGEND]

8 minutes ago, jaapv said:

There are two types of diopter. The smaller ones for the m8/9 and film cameras and larger ones for the newer cameras. Make sure you get the right size. 

Yes, I know this... There is also an adapter with him you can mount smaller diopter from before M10 to the newer cameras...
I will check all info about focusing in M FAQ.
I just complicate things to my self instead to go out and make some photos with my M9M...  

Nikola

[jaapv]

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BTW the M9M is in my opinion the best Monochrom Leica ever made. Hang on to it. 

[Gelatino]

Let me share my own experience:

I should wear glasses but I managed not to do it for 50 years. Actually I used it for night vision. Focussing M10 without any correction was not satifying so I went in a Leica store, tryed several diopters and bought a +1D , that I used  on the M11 too.

Since few months I thought changing the +1D for may be a +1,5 could be usefull, so I tryed it but was not fully convinced, so I didn't buy it. Then I read one M user said he admitted after many tests that his view was faulty and with the right correction on his glasses and no additional diopter on his M he got expected results; so I took off the +1D from my M11, cleaned my glasses and made some tests myself. 

Finally, I wear my glasses during shooting, and the +1D is in its box, may be for sale when I am sure I won't use it never more.

[LEGEND]

9 minutes ago, jaapv said:

BTW the M9M is in my opinion the best Monochrom Leica ever made. Hang on to it. 

I agree, the best Monochrom ever. I love the slow process in making a photograph.
Operating with her like I had on my analog MP. I even lowered the LCD to the minimum
because it is not for anything. I use him only to check the true RAW histogram that I 
find perfect for my workflow.  I had M9M before and used her for 4 years. Purchased 
her new in Germany around 5 months after it came out. Because I payed in cash
I got her in 2 weeks from my Leica dealer... Cash is king as they say...  

But after 4 years I wanted to make colour photos so I sold her for 3000 Euro and 
got used M240. After her I got SL601, M10-D,  SL2, SL2-S and at the end M11...
Always sell one, give some extra money and get next Leica.

Now I got an offer that I could't refuse. Leica M9 Monochrom used, excellent condition,
new sensor, around 10000 shutter actuations , box with papers and 7 batteries...
All that for only 1600 Euro...  I always had luck with Leica cameras and lenses.
Even with customer service when I did CLA of my lux 50 Asph. 

This Leica M9M will stay where it is until I die. In my hand and me looking through the viewfinder
making photos...

Nikola

[jaapv]

Check the sensor version!

[LEGEND]

15 minutes ago, Gelatino said:

Let me share my own experience:

I should wear glasses but I managed not to do it for 50 years. Actually I used it for night vision. Focussing M10 without any correction was not satifying so I went in a Leica store, tryed several diopters and bought a +1D , that I used  on the M11 too.

Since few months I thought changing the +1D for may be a +1,5 could be usefull, so I tryed it but was not fully convinced, so I didn't buy it. Then I read one M user said he admitted after many tests that his view was faulty and with the right correction on his glasses and no additional diopter on his M he got expected results; so I took off the +1D from my M11, cleaned my glasses and made some tests myself. 

Finally, I wear my glasses during shooting, and the +1D is in its box, may be for sale when I am sure I won't use it never more.

Thank you for sharing your experience with this problem.
I think the best is to make your own tests and then decide how to proceed further.

Nikola

 

[LEGEND]

3 minutes ago, jaapv said:

Check the sensor version!

I had already... He provided me with a Leica certificate that he sensor was exchanged in 2016 by Leica
and also I looked into the service menu from my MM (the hidden one). I just pressed the buttons in the right sequence
and the service menu with all the data showed up. There is info about this on the Thorsten Overgaard web site. 
I can put a link where is this to find if someone need it...

Nikola

[TomB_tx]

I wore glasses for nearsightedness and strong astigmatism for over 60 years. With that combination I felt a correction eyepiece was not practical, so just wore glasses even for photography - which was only a problem with old cameras (like early Canon RFs) with tiny peephole eyepieces. My widest M lens was 35mm, which I could use without problem on .72 VFs. However, at age 73 my cataracts reached the point where I had lens replacements, with a "toric" multifocal lenses that also correct astigmatism and give near, mid, and far correction. My eyesight is now 20-20 and I can even use my old peephole Canons easily.

May seem like a drastic solution for VF use, but as your eyesight degrades there is hope, and the world seems like Hi-Def afterwards.

[dpitt]

I have found that if you can not go and compare lenses with your camera, there is an other way to find the best glasses to wear for using the camera. Just find glasses which give you perfect sight at 2m for any live objects without looking through the RF. I found that these glasses (an older pair I can not use to read anymore) work fine for focusing my M9. My current reading glasses are perfect for reading books, and too strong for focusing my M9.

Edited August 13, 2023 by dpitt

[Ko.Fe.]

I'm not optometrist to advise here. Just...

You had this camera for four years and, I assume, used it. Is it possible to use same camera you have now same way as it was in use for four years?

If its VF was modified to something which doesn't match your eyes it might be better to get it restored to original? Instead of trying to correct something wrong with something which could make it worse.

 

[jaapv]

?? There was nothing modified on the camera. A diopter is a regular accessory by Leica for eyesight correction. 

[dpitt]

Its the eyes that change, not the camera.

I understand perfectly. Over 8 years I went from not needing reading glasses to more than +2.0 diopter and astigmatism. That will definitely change the need for optical adjustment to focus correctly.

[Susie]

Hi Nikola,

There is a guy in South Africa who will make a suitable correction lens for you to your perscription.  It screws in like the Leica ones, but can be rotated to accomodate the astigmatism depending on whether you are shooting horizontal or vertical framing.  I will try to find his contact details.

Susie

PM sent 18.19BST

Edited August 14, 2023 by Susie

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[jaapv]

Post # 2. 

[Jeff S]

Indeed, the advice to experiment with diopters is wise.  
 

I wear glasses to correct for astigmatism and distance (and sunglasses in daytime for light sensitivity). But with aging eyes, I now benefit from a +.5 diopter, in addition to my glasses, for optimal focusing. This was determined, as Jaap described, by using trial diopters at my local optician (using my glasses and my M). No way I could have determined this mathematically.

I prefer wearing glasses to the Walker eyepiece (which is bulky and awkward IMO) mostly because I want clear vision when photographing even when my eye isn’t against the VF.

BTW, I recommend using thin, flexible eyeglass frames.

Jeff