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How to determine correct diopter?

Scott Squire - Seattle / Pacific Northwest , Jun 13, 2003; 05:37 p.m.

So I wear (nearsight) correction glasses, most of the time. Often leave them off when shooting. I'd like to make the most of the viewfinder, so how do I determine which (if any) would be the correct diopter? Cheers,


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Cosmo Genovese , Jun 13, 2003; 05:46 p.m.

The only real way to get a correct fit is to go to a Leica Dealer and try the ones nearest your prescription in your camera model's viewfinder. If you're not near a Leica dealer, then you may have to (1) find out your prescription's plus (+) or minus (-) diopter value and then (2) order several from a dealer with the understanding that you can return the ones that don't match your prescription.

Rob F. , Jun 13, 2003; 06:13 p.m.

The last time we got into this, a couple of years ago, it was pointed out that the finder image is presented at a virtual distance of two meters; and that there is some negative diopter correction (trusting my failing memory, I think 1/2 diopter was mentioned) already in the finder. In some way this influences the choice of correction lens you need (I think it does). I don't remember whether it was said that the lens supplied with the camera comes out when you install the new diopter; or if you take the 1/2 diopter figure into account when ordering your personal corrective diopter.

The point being, don't run right out and do anything until a couple of the members who really have this down pat get a chance to respond to this. There is something specific you're supposed to know.

Rob F. , Jun 13, 2003; 06:23 p.m.

Actually, I'm going in for an eye exam next week, and I will simply take an M body along and request that I be measured through the camera, for the best lens correction for my glasses and contacts.

One problem with using corrective lenses, I guess, is that one would have to be constantly putting on and taking off one's eyeglasses, unless the prescription is mild enough to get away without wearing them much of the time. I like to wear contacts for serious shooting, but then at my age I have to put on the 1/2 frame reading glasses to see the camera controls. It's a good argument for shooting my R5, which displays everything in the finder.

Roger Suppona , Jun 13, 2003; 07:13 p.m.

I got tired of the glasses routine and had lasik in January. It's about the price of a M7 and can't correct for tired old eyes (still nead readers). But it's wonderful after 45+ years of glasses to be able to use a viewfinder without diopters or giving up real estate to the distance imposed by glasses.

Yes, you can get lasik for less than the price of an M7 but consider the concept of "discount eye surgery" before jumping in.

Andrew Nemeth , Jun 13, 2003; 07:26 p.m.

Ed Balko , Jun 13, 2003; 07:54 p.m.

I'm an eyeglass wearer and at my last eye exam, I asked the optician for a prescription for the diopter correction lenses to by used on my cameras. He seemed entirely familiar with this.

So far, I've only used the prescription for one camera, a Fuji GS690II, which uses the Nikkor diopter lenses. His prescription seems to be right on the money.

Jay . , Jun 13, 2003; 08:13 p.m.

<<So I wear (nearsight) correction glasses, most of the time. Often leave them off when shooting. I'd like to make the most of the viewfinder, so how do I determine which (if any) would be the correct diopter>>

If you do not have astigmatism in your shooting eye, and you do not need bifocals to see clearly at 2m (about 6ft) you want the Leica diopter that is the closest to your distance Rx. If you have astigmatism (but again, don't need bifocals for 2m) you want the diopter that is 1 diopter stronger than your distance Rx (more negative, ie -3 if your Rx is -2). Optometrists/opthalmologists refer to this as the "spherical equivalent".

If you have no astigmatism, but do need bifocals for 2m, you want to know from your eye doctor what the "add" is for you at 2m...and then add that to your distance Rx. Eg: If your Rx is -3 with a +1.5 "add" for correction at 2m, you get the Leica diopter of -1.5.

Same scenario as above, but with astigmatism: again, one diopter more negative. In the example, you'd need a -2.5 diopter.

bruno menilli , Jun 13, 2003; 08:37 p.m.

Response to How to determine correct dioptre ?

Scott I hope my recent experience may be of some use to you.

Being long sited I only wear glasses for reading and close up use, and my cameras (R8 & MP) being very ergonomic and intuative to use allow me most of the time to feel my way around with out even looking. Of course the R8 shows everthing in the viewfinder, which I have set to +2 dioptre. With the M camera the optical system of the viewfinder seems to be somewhat different, in that although I have read that there is a -0.5 dioptre built in, I can JUST ABOUT get away without a correction lens fitted, but when I did get one I found that a +1.5 dioptre was ok! Very odd but that is what I found out to be the power needed.

Therefore I suppose you just have to experiment with various strengths until you can see clearly.

Good luck.


Ray . , Jun 14, 2003; 12:47 a.m.

Best and easiest solution is to go into a camera store that's got the diopter lenses you can try. My distance prescription is 1.25, not sure if I have astigmatism or not, but I ended up choosing 1.50 for best viewing for distance with my M.

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