Leica Diopters

[DanMitchell]

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Good morning.

Just on the off chance someone else has had this issue... My eye has been tested to have -1.25 and I wondered if anyone had experience with picking the right diopter.

Because the M9 finder is -0.5 I can add a -0.5 to get -1 or add a -1.0 to get -1.5. Is it better to be slightly stronger or slighter weaker than my eye prescription?

Thank you. Dan.

[EvilTed]

I went to a Leica dealer who had all the diopters and magnifiers in stock.

With my M240 being the same -0.5 as the M9, I tried 1.5 and also 1.0.

 

I settled on a 1.0 all the time and a 1.25x magnifier + 1.0 for shooting 50mm.

This works great.Just get yourself one of those rubber filter ring removal kits

 

ET

[CaptZoom]

Dan,

I'm in a similar situation (except mine are -2.25).

Looking forward to hearing some solutions others have come up with.

[Jeff S]

M9 FAQ

 

Plus dozens of threads on this topic via the search box.

 

Bottom line, one should test alternatives at a dealer or an optician, or buy several if there is a return policy. All the math and logic in the world doesn't substitute for real experience. Same basic advice for magnifiers.

 

Each person has his/her own comfort level with viewing practices. I prefer wearing glasses, as my vision requires adjustment for normal distance viewing (and astigmatism), and having a diopter (or Walter eyepiece) correction would require taking them on and off constantly.

 

Jeff

[CaptZoom]

Thanks Jeff, I had no idea diopter a don't account for astigmatism (it's curious why my doctor neglected to mention that when we measured my prescription for a diopter).

[Jeff S]

Thanks Jeff, I had no idea diopter a don't account for astigmatism (it's curious why my doctor neglected to mention that when we measured my prescription for a diopter).

 

But the Walter eyepiece does. I have no experience with it, but others have reported on it here.

 

Jeff

[payasam]

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You could visit your optician and try lenses of different powers between eye and finder to identify the one which works best. But the additional lens may take into account the power built into the finder. I remember buying, several years ago, a diopter marked +1.0 for a film SLR and being unable to use it because its power, as measured by my optician, was +2.0.

[stunsworth]

If you have need of a positive diopter, you could go to a supermarket and try on their reading glasses. Look through the viewfinder wearing glasses of different strengths, and the one that looks clearest tells you which diopter to buy.

[ericborgstrom]

My right, shooting eye is -2.75. I use the -2 diopter on my M and this works well. Tried the -3 diopter but that made the rangefinder fuzzy.

 

Btw It is great having -2.75 as I don´t need reading glasses being 65 years. Driving is an other matter.

[payasam]

Steve, I said in my previous post that the marked strength of a diopter is not always its true optical strength. Certainly they are different where diopters for Canon film SLRs are concerned. What Eric said may be a guide: -2.0 and -0.5 combine to make -2.5, while his near vision prescription is -2.75. My own situation (on the positive side) is this: reading glasses, +2.5; glasses for use with computer, +2.0; attachment lens for view-finders of Leica M6, Hexar RF and Nicca 3-F, all +1.0. The reading glasses prescription would be much too strong for a diopter. I think (not certain) that what's needed is a strength that gives clear vision at the apparent distance of the image in the finder, which is around 2 yards. Two years ago I could not figure out the strength I needed for a Bessa R2A camera. I arranged to buy two and eventually sent back the unwanted one for a refund. They cost under $20 each while the Leica product is around five times as expensive.

[01af]

I remember buying, several years ago, a diopter marked +1.0 dpt for a film SLR and being unable to use it because its power, as measured by my optician, was +2.0 dpt.

It was a Canon brand diopter lens, wasn't it?

[payasam]

Yes, 01af. You missed my next post, second sentence.

[01af]

You missed my next post, second sentence.

Ah, yes. Now I see it.

 

Generally, Canon is known for their weird and entirely stupid system of marking their eyepiece correction lenses. They add the camera's eyepiece's pre-set—which is -1.0 dpt for all their SLR and DSLR models—to the strength of the diopter lens. So if the diopter lens itself actually is +2.0 dpt then they will add -1.0 dpt to this and mark the lens "+1.0". As a consequence, they do offer a "0.0" correction lens which really is +1.0 dpt. And of course there's no "-1.0" correction lens because that's what you're getting with no additional diopter at all.