Do Diopters Help

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Because I do not have great eyesight, I have to use my M6 with my glasses on. My eyes are corrected to +2 and astigmatism, so I really have no choice but to look through my glasses, into the viewfinder. I have often wondered if putting a diopter on the eyepiece will magnify the focus area, thus assisting me in getting a sharp focus. I also use the Hyperfocal technique, and Infinity so as not to have to totally rely on my eyesight.

By the way, thanks for your comments on the sounds my shutter makes at 1/8 etc. P Nelson

-- Paul Nelson (clrfarm@comswest.net.au), January 22, 2001

Answers

I don't know about the astigmatism, but I use a +2 on my M3 and it's a godsend for my 63 year old eyes!

-- Simon Garcia (oldsbg@mindspring.com), January 22, 2001.

The M6 viewfinder is said to be projected at a "virtual" distance of 1-1.5 m depending on which guru you read. The standard M6 eyepiece is fitted with a -0.5 which adds to your glasses Rx. For example, if you look through the finder with your +2 glasses, you are actually getting +1.5. I am (in my right eye that I use with a camera)a -4.25 with astigmatism, for long distances, and a +1.5 "add", or bifocal, (total correction= -4.25 + 1.5 = -2.75) for up-close reading. In the Leica finder, looking through the upper (long distance) part of my bifocals, getting -4.75 (-4.25 + -0.5) I can still see and focus sharply, so I personally believe the virtual distance is much farther than the 1-1.5m that is commonly stated in books. With any SLR, Leica included, I need to dial in a little bit of + diopter to use the distance part of my bifocals. Your Rx being opposite of mine, you might need to go a little more negative (-1 or even -1.5). If you can read reasonably small print at 8-10ft without your glasses this would be a good indication that some minus correction might help.

-- Jay (infinitydt@aol.com), January 22, 2001.

I use a -2 diopter and the image size has been reduced. One thing to take into consideration is the built in -0.5 diopter correction of the viewfinder on the M6.

-- steve nemes (snemes@aol.com), January 22, 2001.

Leica makes a mount for a custom made correction lenses which can be rotated as you switch from horizontal to vertical. This keeps your astigmatism correction aligned properly. Check with your dealer. I think the 0.58x would be a great thing for eyeglass users.

I cannot comment as an expert but my eyes are fine and I do not have to use any corrective lenses to use the viewfinder. It seems to me that if you use a corrective lens that corrects your vision, you will see what I see. My point being you do not have to consider what the designed in diopter is, just correct for your eyesight and everything should be fine.

Cheers

-- John Collier (jbcollier@home.com), January 22, 2001.


I'm learning a lot of interesting things. I didn't know there was a built-in -0.5 diopter lens, or that there's a virtual distance of 1.5 meters. But, are we at risk of getting lost in the woods with technicalities? As I read the original question, Paul just wants to know if a corrective lens would let him use his Leica without eyeglasses. I think we could answer this as "yes."

If the camera has a built-in -1/2 diopter, I guess this is to optimize the finder for the normal eye which needs no correction (in case any airline pilots use a Leica). As John Collier points out, in order for the rest of us to see what airline pilots see in the finder, the required correction ought to be whatever the doctor ordered for the eyeglasses. Take away one lens, substitute another. I think this argument has one possible limitation. When my eye doctor figures my contact lens prescription, she "regresses" the prescription by about (I think) 1/4 diopter because the contact lens is closer to the eye than an eyeglass lens. So it doesn't need to be as strong. The diopter lens installed in the Leica might also be a bit closer to the eye than spectacle lenses, so possibly should be slightly weaker. But then, since the diopter lens would still not be as close to the eye as a contact lens, the regression required might be negligible.

I think the short answer, though, is yes, they work!

Best wishes,

-- Bob Fleischman (RFXMAIL@prodigy.net), January 22, 2001.



As a eyeglass wearer and someone who has tried diopter correction on various cameras, I would like to throw my two cents in on this matter. The downside of the diopter correction is that the phtographer must keep putting on and off the eyeglasses when not directly viewing through the viewfinder. This is not only a bother, but also can lead to loss or damage of one's eyeglasses. I opted for no dip

-- Jack Belen (jbelen@aol.com), January 23, 2001.

I wasn't going to comment, but Jack's and my experience is the same. I tried the diopter route, but it was a constant process of removing and securing my glasses, (I even tried a neck strap for the glasses... not for every neighborhood unless you are very secure), but just gave up. Wearing glasses with my M made me get reintroduced to an old abandoned friend... the 50mm lens, which was easier to use than the 35, due to the increased eye relief.

I don't wear gasses anymore so this is a non issue, but I can remember that juggling glasses was not very fun.

-- Al Smith (smith58@msn.com), January 23, 2001.


If one is nearsighted, then working without eyeglasses amounts to having a sort of built-in magnifier. Nearsighted folks can see things up close better than those with normal vision. This makes it easy to adjust camera controls. The downside is that you can't see so well at a distance unless using the viewfinder. If I'm using a diopter lens, I hang my glasses on a nylon cord around my neck. You know, the kind with adjustable loops that tighten onto the temples. Contact lenses are even better, except there goes your near vision, so now you hang reading glasses from the string.

-- Bob Fleischman (RFXMAIL@prodigy.net), January 23, 2001.

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