MY Diopter Arrived: Great Help

[finnegan]

<p>I have a new "old" Leica M3 with collapsible 50mm Summicron Lens from 1955. Looks new:<br>

http://www.ebay.com/itm/311349810473?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT<br>

I find it hard to focus, like my other rangefinder: Fuji GW690III 6x9. My eyesight is good, no legal need for glasses for driving but it's clearer so I do wear a pair but I use them only for that, never wore glasses in my life. But I know I do have a prescription, wear reading glasses at 1.0 from drug store also.<br>

So, I got a diopter 1.25, I read the M3 had a -0.5 finder lens and figured 1.25 would work well. It did.<br>

Got it from China with an "Offer" on Ebay, regularly $95, my offer was $80 and accepted. It came from China but is a regular Leica diopter.<br>

I is a BIG Difference, easier to focus, much clearer throughout. I urge anyone with even slight vision problems but having focus problems with a Leica M to get one of these. Well worth the 80 bucks!</p>

<p> </p>

[john_stockdale2]

<p>As we become older, the diopter value becomes more critical. Have a look at the graph about three-quarters of the way down this page:</p>

<p>http://en.wikipedia.org/wiki/Eyeglass_prescription</p>

<p>Also, as we age, it is common for those of us who have short sight (and need a -ve diopter) to need a weaker value. My eyes have an accommodation (focus ability for different distances) that's under 0.5 diopter, so the value is critical. When I was young just about any -ve value was ok. Most camera manufacturers have diopters in increments of 1.0 which means that those oldies who need an in-between value are out of luck. Leica has some 0.5 increments for the lower values and that is a great help.</p>

<p>So my point is, I'm surprised that William was able to get a diopter in Leica mount with a value corrected to 0.25 diopter, since the smallest increment I've come across is 0.5. Sure an optician would be able to make any value, but it's not easy to find one who wants to do something out of the ordinary, at least in my experience.</p>

[john_stockdale2]

<p>Actually you're lucky if you need a +ve diopter because the drug store reading glasses can be used to choose the best value. They don't make them in -ve values for obvious reasons!</p>

<p> </p>

[finnegan]

<p>"<a href="/photodb/user?user_id=412357">John Stockdale</a></p>

<blockquote>

<p>So my point is, I'm surprised that William was able to get a diopter in Leica mount with a value corrected to 0.25 diopter, since the smallest increment I've come across is 0.5. Sure an optician would be able to make any value, but it's not easy to find one who wants to do something out of the ordinary, at least in my experience."<br>

</p>

</blockquote>

<p>Just happened to find one on Ebay, bingo! But the corrected value, if you mean what I think you do, is 0.75: 1.25 - 0.5 = 0.75.<br>

Isn't that what you mean by "Value corrected to..", the diopter value which is a positive (1.25) on a negative value finder (-0.5)?</p>

[john_stockdale2]

<p>I meant the increments between values. Most makers have steps of 1.0 diopter between adjacent values, so if you really needed 1.5 you had to choose between 1 and 2.</p>

<p>Leica has 0.5 between some of them, so if you needed, say 0.5 or -1.5 you could get them.</p>

<p>I haven't seen such diopter in 0.25 steps.</p>

[Robert_Lai]

<p>You can also try a magnifier with variable diopter, for example as made by Match optical.<br>

I had a 1.15X magnifier, which combined with the M3's 0.91x magnification gives you a 1:1 overall magnification. That means that you could view through the finder with both eyes open.</p>

<p>It didn't work out for me because I have astigmatism, which I need corrected. But, if you only need a diopter correction, this is an alternative that is appealing.</p>

[ray .]

Pretty sure the Leica diopters come in increments of .5 diopters, so if it's a 1.25 diopter it must be a 3rd

party manufacturer. I suppose though if it works it works. Funny that you say your eyesight is good and

yet you use glasses for both reading and driving. If you can afford to or have insurance it might be best to

go to an optometrist and get what you need instead of relying on cheap drug store glasses. Your eyesight

is precious and yes it does make a big difference having the proper correction!

[finnegan]

<p>Very Interesting, the same thing I just bought is listed on BH Photo as a MAGNIFIER 1.25.</p>

<p>What I had before was from photos is a 1.0 DIOPTER. I can't remember who I bought it from, may have been BH Photo. So, the magnifier helped me more than the diopter.<br>

The magnifier is from top to bottom longer than the diopter, or to put it another way: it sticks out more from the finder. The diopter is flatter.</p>

<p>What I have done is reversed the name. What I thought was the diopter is apparently the magnifier and vis-versa. They are near equal in strength, 1.25 for the magnifier and 1.0 for the diopter. The diopter came in a Leica box. Confusingly it states "Magnifier" on the box.<br>

But from BH Photos the photos show what I stated.</p>

<p>What exactly is the difference between a diopter and a magnifier anyway?</p>

[ray .]

Magnifier just makes the view larger. Diopter is a correction lens for imperfect eyesight. Maybe someone

else can explain it better...

[mukul_dube]

<p>There is no better explanation, but a longer one is possible. If you look in the Leica world for <em>finder magnification</em>, you'll see figures like 0.92 (M3), 0.72 (M2 and later), and, starting with the M6, 0.85 and 0.58. Lower magnifications are best for wide lenses and vice versa. What a magnifier does is change the magnification upwards to give a larger apparent image and make focussing easier and more accurate. There are also reducing units with values under 1x. A "diopter" is a lens which corrects for a defect in vision. Broadly, if you need to wear glasses for any purpose, you are likely to benefit from using such a lens on a camera finder. Like glasses, hypermetropia needs a convex (+ prescription) lens and myopia needs a concave (minus prescription) lens. My experience has been that by far the largest number of photographers need correction on their cameras when they develop presbyopia.</p>

[finnegan]

<p>Thanks for the info.<br>

Well I screwed the diopter into the magnifier. My Leica looks like it has an erection in the back. I looked thru it briefly, seemed good but I haven't used it to shoot yet where I'll be a better judge.</p>

<p>But the length now of the two together may be too unwieldy: to close the case, an original (altho the the leather strap broke, I've ordered another case) without it scratching the diopter, and to look through. It actually looks like a threat to the eye, better have steady hands. Looks like a narrow pipe: if you tripped, or had a bad hand-shake, would go against the eyeball itself perhaps. <br /> No thanks.</p>